Wireless power reception device and wireless power transmission device

ABSTRACT

According to one aspect of the present invention, a wireless power reception device includes: a power pickup circuit configured to form a magnetic coupling with a wireless power transmission device to receive wireless power from the wireless power transmission device; and a communication/control circuit configured to perform transmission control for the wireless power and at least one of data transmission and reception on the basis of communication with the wireless power transmission device, wherein the communication/control circuit can initiate a process for generating an authenticated link for charging by accepting only a connection request received within a prescribed authentication accept period.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present document relates to a wireless power receiver thatwirelessly receives power from a wireless power transmitter, and awireless power transmitter that wirelessly transmits power to thewireless power receiver.

Related Art

The wireless power transfer (or transmission) technology corresponds toa technology that may wirelessly transfer (or transmit) power between apower source and an electronic device. For example, by allowing thebattery of a wireless device, such as a smartphone or a tablet PC, andso on, to be recharged by simply loading the wireless device on awireless charging pad, the wireless power transfer technique may providemore outstanding mobility, convenience, and safety as compared to theconventional wired charging environment, which uses a wired chargingconnector. Apart from the wireless charging of wireless devices, thewireless power transfer technique is raising attention as a replacementfor the conventional wired power transfer environment in diverse fields,such as electric vehicles, Bluetooth earphones, 3D glasses, diversewearable devices, household (or home) electric appliances, furniture,underground facilities, buildings, medical equipment, robots, leisure,and so on.

The wireless power transfer (or transmission) method is also referred toas a contactless power transfer method, or a no point of contact powertransfer method, or a wireless charging method. A wireless powertransfer system may be configured of a wireless power transmittersupplying electric energy by using a wireless power transfer method, anda wireless power receiver receiving the electric energy being suppliedby the wireless power transmitter and supplying the receiving electricenergy to a receiver, such as a battery cell, and so on.

The wireless power transfer technique includes diverse methods, such asa method of transferring power by using magnetic coupling, a method oftransferring power by using radio frequency (RF), a method oftransferring power by using microwaves, and a method of transferringpower by using ultrasound (or ultrasonic waves). The method that isbased on magnetic coupling is categorized as a magnetic induction methodand a magnetic resonance method. The magnetic induction methodcorresponds to a method transmitting power by using electric currentsthat are induced to the coil of the receiver by a magnetic field, whichis generated from a coil battery cell of the transmitter, in accordancewith an electromagnetic coupling between a transmitting coil and areceiving coil. The magnetic resonance method is similar to the magneticinduction method in that is uses a magnetic field. However, the magneticresonance method is different from the magnetic induction method in thatenergy is transmitted due to a concentration of magnetic fields on botha transmitting end and a receiving end, which is caused by the generatedresonance.

Meanwhile, the wireless power transmitter and receiver are designed toexchange various status information and commands related to the wirelesscharging system using in-band communication. However, since in-bandcommunication is not a system designed specifically for communication,it is not suitable for high-speed, large-capacity information exchangeand exchange of various information. Therefore, a method for exchanginginformation related to a wireless charging system by combining anotherwireless communication system (i.e., an out-band communication system)with the existing in-band communication is being discussed. Out-bandcommunication includes, for example, NFC and Bluetooth Low Energy (BLE)communication. BLE is one of the representative out-band communicationtechnologies for wireless charging, and has advantages such as a fastertransmission speed compared to the existing in-band communicationchannel and a convenient data transmission method based on GATT.

In the case of BLE, before a device-to-device connection is established,a process of authenticating whether the device to be connected iscorrect through a passkey entry or numeric comparison on a screen outputis performed. If this process is not performed properly, it isclassified as an unauthenticated link, and it does not guarantee that itis connected to the intended device.

A wireless power transmitter and a wireless power receiver send andreceive important and various information related to wireless powertransmission. In particular, if the parameter information directlyrelated to wireless power transmission is manipulated, property andhuman damage may occur, so the highest level of security is required.Therefore, when the above parameter information is transmitted throughout-band communication such as BLE, it is necessary that anauthenticated link be used.

For example, the passkey entry/numeric comparison method used forauthentication in BLE is available only in devices that support keyboardinput or display output. Wireless power transmitters and wireless powerreceivers currently distributed in the market often do not support it.That is, it is difficult to create an authenticated BLE link for alldevices.

Therefore, by creating an authenticated BLE link between low-specwireless power transmitters or wireless power receivers that do not havea user input interface such as touch display output, and keyboard inputfunction, a wireless power transmitter and method for enhancingsecurity, and a wireless power receiver and method are required.

SUMMARY OF THE DISCLOSURE

An object of the present document is to provide a wireless powertransmitter and method for initiating and establishing a timing-basedauthenticated link procedure, and a wireless power receiver and method.

A wireless power transmitter and method, and a wireless power receiverand method for performing the existing authentication process based onthe elliptic curve Diffie-Hellman (ECDH) public key exchange method areprovided.

Provided are a wireless power transmitter and method, and a wirelesspower receiver and method for performing ECDH public key exchange in asituation where mutual authentication is completed.

A wireless power transmitter and method for generating a mutuallyauthenticated link, and a wireless power receiver and method areprovided.

According to one aspect of the present document, a wireless powerreceiver is provided. The wireless power receiver may comprise a powerpickup circuit configured to form magnetic coupling with the wirelesspower transmitter to receive wireless power from the wireless powertransmitter, and a communication/control circuit configured to performat least one of transmission control of the wireless power andtransmission and reception of data based on communication with thewireless power transmitter, where the communication/control circuittransmits a packet including information about an authenticationinitiator (AI), and a user interface related to changing information onthe authentication initiator may be provided.

According to another aspect of the present document, a wireless powertransmitter is provided. The wireless power transmitter may comprise apower conversion circuit configured to form a magnetic coupling with awireless power receiver to transmit wireless power to the wireless powerreceiver and a communication/control circuit configured to perform atleast one of transmission control of the wireless power and transmissionand reception of data based on communication with the wireless powerreceiver, where the communication/control circuit is configured toinitiate a creation process of an authenticated link for charging byaccepting only a connect request received within a predeterminedauthentication accept period.

According to the present document, it is possible to initiate anauthenticated link creation procedure between the wireless powertransmitter and the wireless power receiver without a separate displayoutput/keyboard input function.

In addition, it is possible to prevent in advance the risk ofcommunication between the wireless power transmitter and the wirelesspower receiver being leaked to the attack device in the process ofcreating an authenticated link.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a wireless power system (10) according toan exemplary embodiment of the present disclosure.

FIG. 2 is a block diagram of a wireless power system (10) according toanother exemplary embodiment of the present disclosure.

FIG. 3a shows an exemplary embodiment of diverse electronic devicesadopting a wireless power transfer system.

FIG. 3b shows an example of a WPC NDEF in a wireless power transfersystem.

FIG. 4a is a block diagram of a wireless power transfer system accordingto another exemplary embodiment of the present disclosure.

FIG. 4b is a diagram illustrating an example of a Bluetoothcommunication architecture to which an embodiment according to thepresent disclosure may be applied.

FIG. 4c is a block diagram illustrating a wireless power transfer systemusing BLE communication according to an example.

FIG. 4d is a block diagram illustrating a wireless power transfer systemusing BLE communication according to another example.

FIG. 5 is a state transition diagram for describing a wireless powertransfer procedure.

FIG. 6 shows a power control method according to an exemplary embodimentof the present disclosure.

FIG. 7 is a block diagram of a wireless power transmitter according toanother exemplary embodiment of the present disclosure.

FIG. 8 shows a wireless power receiver according to another exemplaryembodiment of the present disclosure.

FIG. 9 shows a communication frame structure according to an exemplaryembodiment of the present disclosure.

FIG. 10 is a structure of a sync pattern according to an exemplaryembodiment of the present disclosure.

FIG. 11 shows operation statuses of a wireless power transmitter and awireless power receiver in a shared mode according to an exemplaryembodiment of the present disclosure.

FIG. 12 is a block diagram showing a wireless charging certificateformat according to an exemplary embodiment of the present disclosure.

FIG. 13 is a capability packet structure of a wireless power transmitteraccording to an exemplary embodiment of the present disclosure.

FIG. 14 is a configuration packet structure of a wireless power receiveraccording to an exemplary embodiment of the present disclosure.

FIG. 15 shows an application-level data stream between a wireless powertransmitter and a receiver according to an example.

FIG. 16 is a flowchart illustrating a method of establishing anauthenticated link (authenticated BLE link) based on timing according toan embodiment.

FIG. 17a is a flowchart of an authentication process by Qiauthentication according to an example.

FIG. 17b is a diagram illustrating a packet format of the authenticationresponse message (CHALLANGE_AUTH) of FIG. 17 a.

FIGS. 18a and 18b are block diagrams illustrating an Elliptic CurveIntegrated Encryption Scheme according to an example.

FIG. 19a is a flowchart conceptually showing how to perform the existingauthentication process based on the Elliptic Curve Diffie Hellman (ECDH)public key exchange method according to an example.

FIG. 19b is a diagram illustrating a format of an authenticationresponse message (CHALLANGE_AUTH) of FIG. 19 a.

FIG. 20a is a flowchart illustrating a method of performing ECDH publickey exchange in a situation where mutual authentication is completedaccording to another example.

FIG. 20b is a diagram illustrating a format of a Public KeyRequest/Response Message of FIG. 20 a.

FIG. 21 shows a flowchart illustrating an existing method of creating aBLE link according to an example.

FIG. 22a and FIG. 22b are flowcharts illustrating a method of generatinga mutually authenticated BLE link using the exchanged public keyaccording to the embodiment of FIG. 19 or FIG. 20.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

In this specification, “A or B” may refer to “only A”, “only B” or “bothA and B”. In other words, “A or B” in this specification may beinterpreted as “A and/or B”. For example, in this specification, “A, B,or C” may refer to “only A”, “only B”, “only C”, or any combination of“A, B and C”.

The slash (/) or comma used in this specification may refer to “and/or”.For example, “A/B” may refer to “A and/or B”. Accordingly, “A/B” mayrefer to “only A”, “only B”, or “both A and B”. For example, “A, B, C”may refer to “A, B, or C”.

In this specification, “at least one of A and B” may refer to “only A”,“only B”, or “both A and B”. In addition, in this specification, theexpression of “at least one of A or B” or “at least one of A and/or B”may be interpreted to be the same as “at least one of A and B”.

Also, in this specification, “at least one of A, B and C” may refer to“only A”, “only B”, “only C”, or “any combination of A, B and C”. Also,“at least one of A, B or C” or “at least one of A, B and/or C” may referto “at least one of A, B and C”.

In addition, parentheses used in the present specification may refer to“for example”. Specifically, when indicated as “control information(PDCCH)”, “PDCCH” may be proposed as an example of “controlinformation”. In other words, “control information” in thisspecification is not limited to “PDCCH”, and “PDDCH” may be proposed asan example of “control information”. In addition, even when indicated as“control information (i.e., PDCCH)”, “PDCCH” may be proposed as anexample of “control information”.

In the present specification, technical features that are individuallydescribed in one drawing may be individually or simultaneouslyimplemented. The term “wireless power”, which will hereinafter be usedin this specification, will be used to refer to an arbitrary form ofenergy that is related to an electric field, a magnetic field, and anelectromagnetic field, which is transferred (or transmitted) from awireless power transmitter to a wireless power receiver without usingany physical electromagnetic conductors. The wireless power may also bereferred to as a wireless power signal, and this may refer to anoscillating magnetic flux that is enclosed by a primary coil and asecondary coil. For example, power conversion for wirelessly chargingdevices including mobile phones, cordless phones, iPods, MP3 players,headsets, and so on, within the system will be described in thisspecification. Generally, the basic principle of the wireless powertransfer technique includes, for example, all of a method oftransferring power by using magnetic coupling, a method of transferringpower by using radio frequency (RF), a method of transferring power byusing microwaves, and a method of transferring power by using ultrasound(or ultrasonic waves).

FIG. 1 is a block diagram of a wireless power system (10) according toan exemplary embodiment of the present disclosure.

Referring to FIG. 1, the wireless power system (10) include a wirelesspower transmitter (100) and a wireless power receiver (200).

The wireless power transmitter (100) is supplied with power from anexternal power source (S) and generates a magnetic field. The wirelesspower receiver (200) generates electric currents by using the generatedmagnetic field, thereby being capable of wirelessly receiving power.

Additionally, in the wireless power system (10), the wireless powertransmitter (100) and the wireless power receiver (200) may transceive(transmit and/or receive) diverse information that is required for thewireless power transfer. Herein, communication between the wirelesspower transmitter (100) and the wireless power receiver (200) may beperformed (or established) in accordance with any one of an in-bandcommunication, which uses a magnetic field that is used for the wirelesspower transfer (or transmission), and an out-band communication, whichuses a separate communication carrier. Out-band communication may alsobe referred to as out-of-band communication. Hereinafter, out-bandcommunication will be largely described. Examples of out-bandcommunication may include NFC, Bluetooth, Bluetooth low energy (BLE),and the like.

Herein, the wireless power transmitter (100) may be provided as a fixedtype or a mobile (or portable) type. Examples of the fixed transmittertype may include an embedded type, which is embedded in in-door ceilingsor wall surfaces or embedded in furniture, such as tables, an implantedtype, which is installed in out-door parking lots, bus stops, subwaystations, and so on, or being installed in means of transportation, suchas vehicles or trains. The mobile (or portable) type wireless powertransmitter (100) may be implemented as a part of another device, suchas a mobile device having a portable size or weight or a cover of alaptop computer, and so on.

Additionally, the wireless power receiver (200) should be interpreted asa comprehensive concept including diverse home appliances and devicesthat are operated by being wirelessly supplied with power instead ofdiverse electronic devices being equipped with a battery and a powercable. Typical examples of the wireless power receiver (200) may includeportable terminals, cellular phones, smartphones, personal digitalassistants (PDAs), portable media players (PDPs), Wibro terminals,tablet PCs, phablet, laptop computers, digital cameras, navigationterminals, television, electronic vehicles (EVs), and so on.

FIG. 2 is a block diagram of a wireless power system (10) according toanother exemplary embodiment of the present disclosure.

Referring to FIG. 2, in the wireless power system (10), one wirelesspower receiver (200) or a plurality of wireless power receivers mayexist. Although it is shown in FIG. 1 that the wireless powertransmitter (100) and the wireless power receiver (200) send and receivepower to and from one another in a one-to-one correspondence (orrelationship), as shown in FIG. 2, it is also possible for one wirelesspower transmitter (100) to simultaneously transfer power to multiplewireless power receivers (200-1, 200-2, . . . , 200-M). Mostparticularly, in case the wireless power transfer (or transmission) isperformed by using a magnetic resonance method, one wireless powertransmitter (100) may transfer power to multiple wireless powerreceivers (200-1, 200-2, . . . , 200-M) by using a synchronizedtransport (or transfer) method or a time-division transport (ortransfer) method.

Additionally, although it is shown in FIG. 1 that the wireless powertransmitter (100) directly transfers (or transmits) power to thewireless power receiver (200), the wireless power system (10) may alsobe equipped with a separate wireless power transceiver, such as a relayor repeater, for increasing a wireless power transport distance betweenthe wireless power transmitter (100) and the wireless power receiver(200). In this case, power is delivered to the wireless powertransceiver from the wireless power transmitter (100), and, then, thewireless power transceiver may transfer the received power to thewireless power receiver (200).

Hereinafter, the terms wireless power receiver, power receiver, andreceiver, which are mentioned in this specification, will refer to thewireless power receiver (200). Also, the terms wireless powertransmitter, power transmitter, and transmitter, which are mentioned inthis specification, will refer to the wireless power transmitter (100).

FIG. 3a shows an exemplary embodiment of diverse electronic devicesadopting a wireless power transfer system.

As shown in FIG. 3 a, the electronic devices included in the wirelesspower transfer system are sorted in accordance with the amount oftransmitted power and the amount of received power. Referring to FIG. 3,wearable devices, such as smart watches, smart glasses, head mounteddisplays (HMDs), smart rings, and so on, and mobile electronic devices(or portable electronic devices), such as earphones, remote controllers,smartphones, PDAs, tablet PCs, and so on, may adopt a low-power(approximately 5 W or less or approximately 20 W or less) wirelesscharging method.

Small-sized/Mid-sized electronic devices, such as laptop computers,robot vacuum cleaners, TV receivers, audio devices, vacuum cleaners,monitors, and so on, may adopt a mid-power (approximately 50 W or lessor approximately 200 W or less) wireless charging method. Kitchenappliances, such as mixers, microwave ovens, electric rice cookers, andso on, and personal transportation devices (or other electric devices ormeans of transportation), such as powered wheelchairs, powered kickscooters, powered bicycles, electric cars, and so on may adopt ahigh-power (approximately 2 kW or less or approximately 22 kW or less)wireless charging method.

The electric devices or means of transportation, which are describedabove (or shown in FIG. 1) may each include a wireless power receiver,which will hereinafter be described in detail. Therefore, theabove-described electric devices or means of transportation may becharged (or recharged) by wirelessly receiving power from a wirelesspower transmitter.

Hereinafter, although the present disclosure will be described based ona mobile device adopting the wireless power charging method, this ismerely exemplary. And, therefore, it shall be understood that thewireless charging method according to the present disclosure may beapplied to diverse electronic devices.

A standard for the wireless power transfer (or transmission) includes awireless power consortium (WPC), an air fuel alliance (AFA), and a powermatters alliance (PMA).

The WPC standard defines a baseline power profile (BPP) and an extendedpower profile (EPP). The BPP is related to a wireless power transmitterand a wireless power receiver supporting a power transfer of 5 W, andthe EPP is related to a wireless power transmitter and a wireless powerreceiver supporting the transfer of a power range greater than 5 W andless than 30 W.

Diverse wireless power transmitters and wireless power receivers eachusing a different power level may be covered by each standard and may besorted by different power classes or categories.

For example, the WPC may categorize (or sort) the wireless powertransmitters and the wireless power receivers as PC-1, PC0, PC1, andPC2, and the WPC may provide a standard document (or specification) foreach power class (PC). The PC-1 standard relates to wireless powertransmitters and receivers providing a guaranteed power of less than 5W. The application of PC-1 includes wearable devices, such as smartwatches.

The PC0 standard relates to wireless power transmitters and receiversproviding a guaranteed power of 5 W. The PC0 standard includes an EPPhaving a guaranteed power ranges that extends to 30 W. Although in-band(IB) communication corresponds to a mandatory communication protocol ofPC0, out-of-band (OB) communication that is used as an optional backupchannel may also be used for PC0. The wireless power receiver may beidentified by setting up an OB flag, which indicates whether or not theOB is supported, within a configuration packet. A wireless powertransmitter supporting the OB may enter an OB handover phase bytransmitting a bit-pattern for an OB handover as a response to theconfiguration packet. The response to the configuration packet maycorrespond to an NAK, an ND, or an 8-bit pattern that is newly defined.The application of the PC0 includes smartphones.

The PC1 standard relates to wireless power transmitters and receiversproviding a guaranteed power ranging from 30 W to 150 W. OB correspondsto a mandatory communication channel for PC1, and IB is used forinitialization and link establishment to OB. The wireless powertransmitter may enter an OB handover phase by transmitting a bit-patternfor an OB handover as a response to the configuration packet. Theapplication of the PC1 includes laptop computers or power tools.

The PC2 standard relates to wireless power transmitters and receiversproviding a guaranteed power ranging from 200 W to 2 kW, and itsapplication includes kitchen appliances.

As described above, the PCs may be differentiated in accordance with therespective power levels. And, information on whether or not thecompatibility between the same PCs is supported may be optional ormandatory. Herein, the compatibility between the same PCs indicates thatpower transfer/reception between the same PCs is possible. For example,in case a wireless power transmitter corresponding to PC x is capable ofperforming charging of a wireless power receiver having the same PC x,it may be understood that compatibility is maintained between the samePCs. Similarly, compatibility between different PCs may also besupported. Herein, the compatibility between different PCs indicatesthat power transfer/reception between different PCs is also possible.For example, in case a wireless power transmitter corresponding to PC xis capable of performing charging of a wireless power receiver having PCy, it may be understood that compatibility is maintained between thedifferent PCs.

The support of compatibility between PCs corresponds to an extremelyimportant issue in the aspect of user experience and establishment ofinfrastructure. Herein, however, diverse problems, which will bedescribed below, exist in maintaining the compatibility between PCs.

In case of the compatibility between the same PCs, for example, in caseof a wireless power receiver using a lap-top charging method, whereinstable charging is possible only when power is continuously transferred,even if its respective wireless power transmitter has the same PC, itmay be difficult for the corresponding wireless power receiver to stablyreceive power from a wireless power transmitter of the power toolmethod, which transfers power non-continuously. Additionally, in case ofthe compatibility between different PCs, for example, in case a wirelesspower transmitter having a minimum guaranteed power of 200 W transferspower to a wireless power receiver having a maximum guaranteed power of5 W, the corresponding wireless power receiver may be damaged due to anovervoltage. As a result, it may be inappropriate (or difficult) to usethe PS as an index/reference standard representing/indicating thecompatibility.

Wireless power transmitters and receivers may provide a very convenientuser experience and interface (UX/UI). That is, a smart wirelesscharging service may be provided, and the smart wireless chargingservice may be implemented based on a UX/UI of a smartphone including awireless power transmitter. For these applications, an interface betweena processor of a smartphone and a wireless charging receiver allows for“drop and play” two-way communication between the wireless powertransmitter and the wireless power receiver.

As an example, a user may experience a smart wireless charging servicein a hotel. When the user enters a hotel room and puts a smartphone on awireless charger in the room, the wireless charger transmits wirelesspower to the smartphone and the smartphone receives wireless power. Inthis process, the wireless charger transmits information on the smartwireless charging service to the smartphone. When it is detected thatthe smartphone is located on the wireless charger, when it is detectedthat wireless power is received, or when the smartphone receivesinformation on the smart wireless charging service from the wirelesscharger, the smartphone enters a state of inquiring the user aboutagreement (opt-in) of supplemental features. To this end, the smartphonemay display a message on a screen in a manner with or without an alarmsound. An example of the message may include the phrase “Welcome to ###hotel. Select “Yes” to activate smart charging functions: Yes|NoThanks.” The smartphone receives an input from the user who selects Yesor No Thanks, and performs a next procedure selected by the user. If Yesis selected, the smartphone transmits corresponding information to thewireless charger. The smartphone and the wireless charger perform thesmart charging function together.

The smart wireless charging service may also include receiving WiFicredentials auto-filled. For example, the wireless charger transmits theWiFi credentials to the smartphone, and the smartphone automaticallyinputs the WiFi credentials received from the wireless charger byrunning an appropriate application.

The smart wireless charging service may also include running a hotelapplication that provides hotel promotions or obtaining remotecheck-in/check-out and contact information.

As another example, the user may experience the smart wireless chargingservice in a vehicle. When the user gets in the vehicle and puts thesmartphone on the wireless charger, the wireless charger transmitswireless power to the smartphone and the smartphone receives wirelesspower. In this process, the wireless charger transmits information onthe smart wireless charging service to the smartphone. When it isdetected that the smartphone is located on the wireless charger, whenwireless power is detected to be received, or when the smartphonereceives information on the smart wireless charging service from thewireless charger, the smartphone enters a state of inquiring the userabout checking identity.

In this state, the smartphone is automatically connected to the vehiclevia WiFi and/or Bluetooth. The smartphone may display a message on thescreen in a manner with or without an alarm sound. An example of themessage may include a phrase of “Welcome to your car. Select “Yes” tosynch device with in-car controls: Yes|No Thanks.” Upon receiving theuser's input to select Yes or No Thanks, the smartphone performs a nextprocedure selected by the user. If Yes is selected, the smartphonetransmits corresponding information to the wireless charger. Inaddition, the smartphone and the wireless charger may run an in-vehiclesmart control function together by driving in-vehicleapplication/display software. The user may enjoy the desired music andcheck a regular map location. The in-vehicle applications/displaysoftware may include an ability to provide synchronous access forpassers-by.

As another example, the user may experience smart wireless charging athome. When the user enters the room and puts the smartphone on thewireless charger in the room, the wireless charger transmits wirelesspower to the smartphone and the smartphone receives wireless power. Inthis process, the wireless charger transmits information on the smartwireless charging service to the smartphone. When it is detected thatthe smartphone is located on the wireless charger, when wireless poweris detected to be received, or when the smartphone receives informationon the smart wireless charging service from the wireless charger, thesmartphone enters a state of inquiring the user about agreement (opt-in)of supplemental features. To this end, the smartphone may display amessage on the screen in a manner with or without an alarm sound. Anexample of the message may include a phrase such as “Hi xxx, Would youlike to activate night mode and secure the building?: Yes|No Thanks.”The smartphone receives a user input to select Yes or No Thanks andperforms a next procedure selected by the user. If Yes is selected, thesmartphone transmits corresponding information to the wireless charger.The smartphones and the wireless charger may recognize at least user'spattern and recommend the user to lock doors and windows, turn offlights, or set an alarm.

Hereinafter, ‘profiles’ will be newly defined based on indexes/referencestandards representing/indicating the compatibility. More specifically,it may be understood that by maintaining compatibility between wirelesspower transmitters and receivers having the same ‘profile’, stable powertransfer/reception may be performed, and that power transfer/receptionbetween wireless power transmitters and receivers having different‘profiles’ cannot be performed. The ‘profiles’ may be defined inaccordance with whether or not compatibility is possible and/or theapplication regardless of (or independent from) the power class.

For example, the profile may be sorted into 3 different categories, suchas i) Mobile, ii) Power tool and iii) Kitchen.

For another example, the profile may be sorted into 4 differentcategories, such as i) Mobile, ii) Power tool, iii) Kitchen, and iv)Wearable.

In case of the ‘Mobile’ profile, the PC may be defined as PC0 and/orPC1, the communication protocol/method may be defined as IB and OBcommunication, and the operation frequency may be defined as 87 to 205kHz, and smartphones, laptop computers, and so on, may exist as theexemplary application.

In case of the ‘Power tool’ profile, the PC may be defined as PC1, thecommunication protocol/method may be defined as IB communication, andthe operation frequency may be defined as 87 to 145 kHz, and powertools, and so on, may exist as the exemplary application.

In case of the ‘Kitchen’ profile, the PC may be defined as PC2, thecommunication protocol/method may be defined as NFC-based communication,and the operation frequency may be defined as less than 100 kHz, andkitchen/home appliances, and so on, may exist as the exemplaryapplication.

In the case of power tools and kitchen profiles, NFC communication maybe used between the wireless power transmitter and the wireless powerreceiver. The wireless power transmitter and the wireless power receivermay confirm that they are NFC devices with each other by exchanging WPCNFC data exchange profile format (NDEF).

FIG. 3b shows an example of a WPC NDEF in a wireless power transfersystem.

Referring to FIG. 3 b, the WPC NDEF may include, for example, anapplication profile field (e.g., 1 B), a version field (e.g., 1 B), andprofile specific data (e.g., 1 B). The application profile fieldindicates whether the corresponding device is i) mobile and computing,ii) power tool, and iii) kitchen, and an upper nibble in the versionfield indicates a major version and a lower nibble indicates a minorversion. In addition, profile-specific data defines content for thekitchen.

In case of the ‘Wearable’ profile, the PC may be defined as PC-1, thecommunication protocol/method may be defined as IB communication, andthe operation frequency may be defined as 87 to 205 kHz, and wearabledevices that are worn by the users, and so on, may exist as theexemplary application.

It may be mandatory to maintain compatibility between the same profiles,and it may be optional to maintain compatibility between differentprofiles.

The above-described profiles (Mobile profile, Power tool profile,Kitchen profile, and Wearable profile) may be generalized and expressedas first to nth profile, and a new profile may be added/replaced inaccordance with the WPC standard and the exemplary embodiment.

In case the profile is defined as described above, the wireless powertransmitter may optionally perform power transfer only to the wirelesspower receiving corresponding to the same profile as the wireless powertransmitter, thereby being capable of performing a more stable powertransfer. Additionally, since the load (or burden) of the wireless powertransmitter may be reduced and power transfer is not attempted to awireless power receiver for which compatibility is not possible, therisk of damage in the wireless power receiver may be reduced.

PC1 of the ‘Mobile’ profile may be defined by being derived from anoptional extension, such as OB, based on PC0. And, the ‘Power tool’profile may be defined as a simply modified version of the PC1 ‘Mobile’profile. Additionally, up until now, although the profiles have beendefined for the purpose of maintaining compatibility between the sameprofiles, in the future, the technology may be evolved to a level ofmaintaining compatibility between different profiles. The wireless powertransmitter or the wireless power receiver may notify (or announce) itsprofile to its counterpart by using diverse methods.

In the AFA standard, the wireless power transmitter is referred to as apower transmitting unit (PTU), and the wireless power receiver isreferred to as a power receiving unit (PRU). And, the PTU is categorizedto multiple classes, as shown in Table 1, and the PRU is categorized tomultiple classes, as shown in Table 2.

TABLE 1 Minimum category Minimum value support for a maximum number PTUPTX_IN_MAX requirement of supported devices Class 1  2 W l× Category 1l× Category 1 Class 2 10 W l× Category 3 2× Category 2 Class 3 16 W l×Category 4 2× Category 3 Class 4 33 W l× Category 5 3× Category 3 Class5 50 W l× Category 6 4× Category 3 Class 6 70 W l× Category 7 5×Category 3

TABLE 2 PRU P_(RX)_OUT_MAX’ Exemplary application Category 1 TBDBluetooth headset Category 2  3.5 W Feature phone Category 3  6.5 WSmartphone Category 4   13 W Tablet PC, Phablet Category 5   25 W Smallform factor laptop Category 6 37.5 W General laptop Category 7   50 WHome appliance

As shown in Table 1, a maximum output power capability of Class n PTUmay be equal to or greater than the P_(TX_IN_MAX) of the correspondingclass. The PRU cannot draw a power that is higher than the power levelspecified in the corresponding category. FIG. 4a is a block diagram of awireless power transfer system according to another exemplary embodimentof the present disclosure.

Referring to FIG. 4 a, the wireless power transfer system (10) includesa mobile device (450), which wirelessly receives power, and a basestation (400), which wirelessly transmits power.

As a device providing induction power or resonance power, the basestation (400) may include at least one of a wireless power transmitter(100) and a system unit (405). The wireless power transmitter (100) maytransmit induction power or resonance power and may control thetransmission. The wireless power transmitter (100) may include a powerconversion unit (110) converting electric energy to a power signal bygenerating a magnetic field through a primary coil (or primary coils),and a communications & control unit (120) controlling the communicationand power transfer between the wireless power receiver (200) in order totransfer power at an appropriate (or suitable) level. The system unit(405) may perform input power provisioning, controlling of multiplewireless power transmitters, and other operation controls of the basestation (400), such as user interface control.

The primary coil may generate an electromagnetic field by using analternating current power (or voltage or current). The primary coil issupplied with an alternating current power (or voltage or current) of aspecific frequency, which is being outputted from the power conversionunit (110). And, accordingly, the primary coil may generate a magneticfield of the specific frequency. The magnetic field may be generated ina non-radial shape or a radial shape. And, the wireless power receiver(200) receives the generated magnetic field and then generates anelectric current. In other words, the primary coil wirelessly transmitspower.

In the magnetic induction method, a primary coil and a secondary coilmay have randomly appropriate shapes. For example, the primary coil andthe secondary coil may correspond to copper wire being wound around ahigh-permeability formation, such as ferrite or a non-crystalline metal.The primary coil may also be referred to as a transmitting coil, aprimary core, a primary winding, a primary loop antenna, and so on.Meanwhile, the secondary coil may also be referred to as a receivingcoil, a secondary core, a secondary winding, a secondary loop antenna, apickup antenna, and so on.

In case of using the magnetic resonance method, the primary coil and thesecondary coil may each be provided in the form of a primary resonanceantenna and a secondary resonance antenna. The resonance antenna mayhave a resonance structure including a coil and a capacitor. At thispoint, the resonance frequency of the resonance antenna may bedetermined by the inductance of the coil and a capacitance of thecapacitor. Herein, the coil may be formed to have a loop shape. And, acore may be placed inside the loop. The core may include a physicalcore, such as a ferrite core, or an air core.

The energy transmission (or transfer) between the primary resonanceantenna and the second resonance antenna may be performed by a resonancephenomenon occurring in the magnetic field. When a near fieldcorresponding to a resonance frequency occurs in a resonance antenna,and in case another resonance antenna exists near the correspondingresonance antenna, the resonance phenomenon refers to a highly efficientenergy transfer occurring between the two resonance antennas that arecoupled with one another. When a magnetic field corresponding to theresonance frequency is generated between the primary resonance antennaand the secondary resonance antenna, the primary resonance antenna andthe secondary resonance antenna resonate with one another. And,accordingly, in a general case, the magnetic field is focused toward thesecond resonance antenna at a higher efficiency as compared to a casewhere the magnetic field that is generated from the primary antenna isradiated to a free space. And, therefore, energy may be transferred tothe second resonance antenna from the first resonance antenna at a highefficiency. The magnetic induction method may be implemented similarlyto the magnetic resonance method. However, in this case, the frequencyof the magnetic field is not required to be a resonance frequency.Nevertheless, in the magnetic induction method, the loops configuringthe primary coil and the secondary coil are required to match oneanother, and the distance between the loops should be very close-ranged.

Although it is not shown in the drawing, the wireless power transmitter(100) may further include a communication antenna. The communicationantenna may transmit and/or receive a communication signal by using acommunication carrier apart from the magnetic field communication. Forexample, the communication antenna may transmit and/or receivecommunication signals corresponding to Wi-Fi, Bluetooth, Bluetooth LE,ZigBee, NFC, and so on.

The communications & control unit (120) may transmit and/or receiveinformation to and from the wireless power receiver (200). Thecommunications & control unit (120) may include at least one of an IBcommunication module and an OB communication module.

The IB communication module may transmit and/or receive information byusing a magnetic wave, which uses a specific frequency as its centerfrequency. For example, the communications & control unit (120) mayperform in-band (IB) communication by transmitting communicationinformation on the operating frequency of wireless power transferthrough the primary coil or by receiving communication information onthe operating frequency through the primary coil. At this point, thecommunications & control unit (120) may load information in the magneticwave or may interpret the information that is carried by the magneticwave by using a modulation scheme, such as binary phase shift keying(BPSK), Frequency Shift Keying (FSK) or amplitude shift keying (ASK),and so on, or a coding scheme, such as Manchester coding ornon-return-to-zero level (NZR-L) coding, and so on. By using theabove-described IB communication, the communications & control unit(120) may transmit and/or receive information to distances of up toseveral meters at a data transmission rate of several kbps.

The OB communication module may also perform out-of-band communicationthrough a communication antenna. For example, the communications &control unit (120) may be provided to a near field communication module.Examples of the near field communication module may includecommunication modules, such as Wi-Fi, Bluetooth, Bluetooth LE, ZigBee,NFC, and so on.

The communications & control unit (120) may control the overalloperations of the wireless power transmitter (100). The communications &control unit (120) may perform calculation and processing of diverseinformation and may also control each configuration element of thewireless power transmitter (100).

The communications & control unit (120) may be implemented in a computeror a similar device as hardware, software, or a combination of the same.When implemented in the form of hardware, the communications & controlunit (120) may be provided as an electronic circuit performing controlfunctions by processing electrical signals. And, when implemented in theform of software, the communications & control unit (120) may beprovided as a program that operates the communications & control unit(120).

By controlling the operating point, the communications & control unit(120) may control the transmitted power. The operating point that isbeing controlled may correspond to a combination of a frequency (orphase), a duty cycle, a duty ratio, and a voltage amplitude. Thecommunications & control unit (120) may control the transmitted power byadjusting any one of the frequency (or phase), the duty cycle, the dutyratio, and the voltage amplitude. Additionally, the wireless powertransmitter (100) may supply a consistent level of power, and thewireless power receiver (200) may control the level of received power bycontrolling the resonance frequency.

The mobile device (450) includes a wireless power receiver (200)receiving wireless power through a secondary coil, and a load (455)receiving and storing the power that is received by the wireless powerreceiver (200) and supplying the received power to the device.

The wireless power receiver (200) may include a power pick-up unit (210)and a communications & control unit (220). The power pick-up unit (210)may receive wireless power through the secondary coil and may convertthe received wireless power to electric energy. The power pick-up unit(210) rectifies the alternating current (AC) signal, which is receivedthrough the secondary coil, and converts the rectified signal to adirect current (DC) signal. The communications & control unit (220) maycontrol the transmission and reception of the wireless power (transferand reception of power).

The secondary coil may receive wireless power that is being transmittedfrom the wireless power transmitter (100). The secondary coil mayreceive power by using the magnetic field that is generated in theprimary coil. Herein, in case the specific frequency corresponds aresonance frequency, magnetic resonance may occur between the primarycoil and the secondary coil, thereby allowing power to be transferredwith greater efficiency.

Although it is not shown in FIG. 4 a, the communications & control unit(220) may further include a communication antenna. The communicationantenna may transmit and/or receive a communication signal by using acommunication carrier apart from the magnetic field communication. Forexample, the communication antenna may transmit and/or receivecommunication signals corresponding to Wi-Fi, Bluetooth, Bluetooth LE,ZigBee, NFC, and so on.

The communications & control unit (220) may transmit and/or receiveinformation to and from the wireless power transmitter (100). Thecommunications & control unit (220) may include at least one of an IBcommunication module and an OB communication module.

The IB communication module may transmit and/or receive information byusing a magnetic wave, which uses a specific frequency as its centerfrequency. For example, the communications & control unit (220) mayperform IB communication by loading information in the magnetic wave andby transmitting the information through the secondary coil or byreceiving a magnetic wave carrying information through the secondarycoil. At this point, the communications & control unit (120) may loadinformation in the magnetic wave or may interpret the information thatis carried by the magnetic wave by using a modulation scheme, such asbinary phase shift keying (BPSK), Frequency Shift Keying (FSK) oramplitude shift keying (ASK), and so on, or a coding scheme, such asManchester coding or non-return-to-zero level (NZR-L) coding, and so on.By using the above-described IB communication, the communications &control unit (220) may transmit and/or receive information to distancesof up to several meters at a data transmission rate of several kbps.

The OB communication module may also perform out-of-band communicationthrough a communication antenna. For example, the communications &control unit (220) may be provided to a near field communication module.

Examples of the near field communication module may includecommunication modules, such as Wi-Fi, Bluetooth, Bluetooth LE, ZigBee,NFC, and so on.

The communications & control unit (220) may control the overalloperations of the wireless power receiver (200). The communications &control unit (220) may perform calculation and processing of diverseinformation and may also control each configuration element of thewireless power receiver (200).

The communications & control unit (220) may be implemented in a computeror a similar device as hardware, software, or a combination of the same.When implemented in the form of hardware, the communications & controlunit (220) may be provided as an electronic circuit performing controlfunctions by processing electrical signals. And, when implemented in theform of software, the communications & control unit (220) may beprovided as a program that operates the communications & control unit(220).

When the communication/control circuit 120 and the communication/controlcircuit 220 are Bluetooth or Bluetooth LE as an OB communication moduleor a short-range communication module, the communication/control circuit120 and the communication/control circuit 220 may each be implementedand operated with a communication architecture as shown in FIG. 4 b.

FIG. 4b is a diagram illustrating an example of a Bluetoothcommunication architecture to which an embodiment according to thepresent disclosure may be applied.

Referring to FIG. 4 b, (a) of FIG. 4b shows an example of a protocolstack of Bluetooth basic rate (BR)/enhanced data rate (EDR) supportingGATT, and (b) shows an example of Bluetooth low energy (BLE) protocolstack.

Specifically, as shown in (a) of FIG. 4 b, the Bluetooth BR/EDR protocolstack may include an upper control stack 460 and a lower host stack 470based on a host controller interface (HCI) 18.

The host stack (or host module) 470 refers to hardware for transmittingor receiving a Bluetooth packet to or from a wirelesstransmission/reception module which receives a Bluetooth signal of 2.4GHz, and the controller stack 460 is connected to the Bluetooth moduleto control the Bluetooth module and perform an operation.

The host stack 470 may include a BR/EDR PHY layer 12, a BR/EDR basebandlayer 14, and a link manager layer 16.

The BR/EDR PHY layer 12 is a layer that transmits and receives a 2.4 GHzradio signal, and in the case of using Gaussian frequency shift keying(GFSK) modulation, the BR/EDR PHY layer 12 may transmit data by hopping79 RF channels.

The BR/EDR baseband layer 14 serves to transmit a digital signal,selects a channel sequence for hopping 1400 times per second, andtransmits a time slot with a length of 625 us for each channel.

The link manager layer 16 controls an overall operation (link setup,control, security) of Bluetooth connection by utilizing a link managerprotocol (LMP).

The link manager layer 16 may perform the following functions.

-   -   Performs ACL/SCO logical transport, logical link setup, and        control.    -   Detach: It interrupts connection and informs a counterpart        device about a reason for the interruption.    -   Performs power control and role switch.    -   Performs security (authentication, pairing, encryption)        function.

The host controller interface layer 18 provides an interface between ahost module and a controller module so that a host provides commands anddata to the controller and the controller provides events and data tothe host.

The host stack (or host module, 470) includes a logical link control andadaptation protocol (L2CAP) 21, an attribute protocol 22, a genericattribute profile (GATT) 23, a generic access profile (GAP) 24, and aBR/EDR profile 25.

The logical link control and adaptation protocol (L2CAP) 21 may provideone bidirectional channel for transmitting data to a specific protocolor profile.

The L2CAP 21 may multiplex various protocols, profiles, etc., providedfrom upper Bluetooth.

L2CAP of Bluetooth BR/EDR uses dynamic channels, supports protocolservice multiplexer, retransmission, streaming mode, and providessegmentation and reassembly, per-channel flow control, and errorcontrol.

The generic attribute profile (GATT) 23 may be operable as a protocolthat describes how the attribute protocol 22 is used when services areconfigured. For example, the generic attribute profile 23 may beoperable to specify how ATT attributes are grouped together intoservices and may be operable to describe features associated withservices.

Accordingly, the generic attribute profile 23 and the attributeprotocols (ATT) 22 may use features to describe device's state andservices, how features are related to each other, and how they are used.

The attribute protocol 22 and the BR/EDR profile 25 define a service(profile) using Bluetooth BR/EDR and an application protocol forexchanging these data, and the generic access profile (GAP) 24 definesdevice discovery, connectivity, and security level.

As shown in (b) of FIG. 4 b, the Bluetooth LE protocol stack includes acontroller stack 480 operable to process a wireless device interfaceimportant in timing and a host stack 490 operable to process high leveldata.

First, the controller stack 480 may be implemented using a communicationmodule that may include a Bluetooth wireless device, for example, aprocessor module that may include a processing device such as amicroprocessor.

The host stack 490 may be implemented as a part of an OS running on aprocessor module or as an instantiation of a package on the OS.

In some cases, the controller stack and the host stack may be run orexecuted on the same processing device in a processor module.

The controller stack 480 includes a physical layer (PHY) 32, a linklayer 34, and a host controller interface 36.

The physical layer (PHY, wireless transmission/reception module) 32 is alayer that transmits and receives a 2.4 GHz radio signal and usesGaussian frequency shift keying (GFSK) modulation and a frequencyhopping scheme including 40 RF channels.

The link layer 34, which serves to transmit or receive Bluetoothpackets, creates connections between devices after performingadvertising and scanning functions using 3 advertising channels andprovides a function of exchanging data packets of up to 257 bytesthrough 37 data channels.

The host stack includes a generic access profile (GAP) 45, a logicallink control and adaptation protocol (L2CAP, 41), a security manager(SM) 42, and an attribute protocol (ATT) 43, a generic attribute profile(GATT) 44, a generic access profile 45, and an LE profile 46. However,the host stack 490 is not limited thereto and may include variousprotocols and profiles.

The host stack multiplexes various protocols, profiles, etc., providedfrom upper Bluetooth using L2CAP.

First, the logical link control and adaptation protocol (L2CAP) 41 mayprovide one bidirectional channel for transmitting data to a specificprotocol or profile.

The L2CAP 41 may be operable to multiplex data between higher layerprotocols, segment and reassemble packages, and manage multicast datatransmission.

In Bluetooth LE, three fixed channels (one for signaling CH, one forsecurity manager, and one for attribute protocol) are basically used.Also, a dynamic channel may be used as needed.

Meanwhile, a basic channel/enhanced data rate (BR/EDR) uses a dynamicchannel and supports protocol service multiplexer, retransmission,streaming mode, and the like.

The security manager (SM) 42 is a protocol for authenticating devicesand providing key distribution.

The attribute protocol (ATT) 43 defines a rule for accessing data of acounterpart device in a server-client structure. The ATT has thefollowing 6 message types (request, response, command, notification,indication, confirmation).

{circle around (1)} Request and Response message: A request message is amessage for requesting specific information from the client device tothe server device, and the response message is a response message to therequest message, which is a message transmitted from the server deviceto the client device.

{circle around (2)} Command message: It is a message transmitted fromthe client device to the server device in order to indicate a command ofa specific operation. The server device does not transmit a responsewith respect to the command message to the client device.

{circle around (3)} Notification message: It is a message transmittedfrom the server device to the client device in order to notify an event,or the like. The client device does not transmit a confirmation messagewith respect to the notification message to the server device.

{circle around (4)} Indication and confirmation message: It is a messagetransmitted from the server device to the client device in order tonotify an event, or the like. Unlike the notification message, theclient device transmits a confirmation message regarding the indicationmessage to the server device.

In the present disclosure, when the GATT profile using the attributeprotocol (ATT) 43 requests long data, a value regarding a data length istransmitted to allow a client to clearly know the data length, and acharacteristic value may be received from a server by using a universalunique identifier (UUID).

The generic access profile (GAP) 45, a layer newly implemented for theBluetooth LE technology, is used to select a role for communicationbetween Bluetooth LED devices and to control how a multi-profileoperation takes place.

Also, the generic access profile (GAP) 45 is mainly used for devicediscovery, connection generation, and security procedure part, defines ascheme for providing information to a user, and defines types ofattributes as follows.

{circle around (1)} Service: It defines a basic operation of a device bya combination of behaviors related to data

{circle around (2)} Include: It defines a relationship between services

{circle around (3)} Characteristics: It is a data value used in a server

{circle around (4)} Behavior: It is a format that may be read by acomputer defined by a UUID (value type).

The LE profile 46, including profiles dependent upon the GATT, is mainlyapplied to a Bluetooth LE device. The LE profile 46 may include, forexample, Battery, Time, FindMe, Proximity, Time, Object DeliveryService, and the like, and details of the GATT-based profiles are asfollows.

{circle around (1)} Battery: Battery information exchanging method

{circle around (2)} Time: Time information exchanging method

{circle around (3)} FindMe: Provision of alarm service according todistance

{circle around (4)} Proximity: Battery information exchanging method

{circle around (5)} Time: Time information exchanging method

The generic attribute profile (GATT) 44 may operate as a protocoldescribing how the attribute protocol (ATT) 43 is used when services areconfigured. For example, the GATT 44 may operate to define how ATTattributes are grouped together with services and operate to describefeatures associated with services.

Thus, the GATT 44 and the ATT 43 may use features in order to describestatus and services of a device and describe how the features arerelated and used.

Hereinafter, procedures of the Bluetooth low energy (BLE) technologywill be briefly described.

The BLE procedure may be classified as a device filtering procedure, anadvertising procedure, a scanning procedure, a discovering procedure,and a connecting procedure.

Device Filtering Procedure

The device filtering procedure is a method for reducing the number ofdevices performing a response with respect to a request, indication,notification, and the like, in the controller stack.

When requests are received from all the devices, it is not necessary torespond thereto, and thus, the controller stack may perform control toreduce the number of transmitted requests to reduce power consumption.

An advertising device or scanning device may perform the devicefiltering procedure to limit devices for receiving an advertisingpacket, a scan request or a connection request.

Here, the advertising device refers to a device transmitting anadvertising event, that is, a device performing an advertisement and isalso termed an advertiser.

The scanning device refers to a device performing scanning, that is, adevice transmitting a scan request.

In the BLE, in a case in which the scanning device receives someadvertising packets from the advertising device, the scanning deviceshould transmit a scan request to the advertising device.

However, in a case in which a device filtering procedure is used so ascan request transmission is not required, the scanning device maydisregard the advertising packets transmitted from the advertisingdevice.

Even in a connection request process, the device filtering procedure maybe used. In a case in which device filtering is used in the connectionrequest process, it is not necessary to transmit a response with respectto the connection request by disregarding the connection request.

Advertising Procedure

The advertising device performs an advertising procedure to performundirected broadcast to devices within a region.

Here, the undirected broadcast is advertising toward all the devices,rather than broadcast toward a specific device, and all the devices mayscan advertising to make an supplemental information request or aconnection request.

In contrast, directed advertising may make an supplemental informationrequest or a connection request by scanning advertising for only adevice designated as a reception device.

The advertising procedure is used to establish a Bluetooth connectionwith an initiating device nearby.

Or, the advertising procedure may be used to provide periodicalbroadcast of user data to scanning devices performing listening in anadvertising channel.

In the advertising procedure, all the advertisements (or advertisingevents) are broadcast through an advertisement physical channel.

The advertising devices may receive scan requests from listening devicesperforming listening to obtain additional user data from advertisingdevices. The advertising devices transmit responses with respect to thescan requests to the devices which have transmitted the scan requests,through the same advertising physical channels as the advertisingphysical channels in which the scan requests have been received.

Broadcast user data sent as part of advertising packets are dynamicdata, while the scan response data is generally static data.

The advertisement device may receive a connection request from aninitiating device on an advertising (broadcast) physical channel. If theadvertising device has used a connectable advertising event and theinitiating device has not been filtered according to the devicefiltering procedure, the advertising device may stop advertising andenter a connected mode. The advertising device may start advertisingafter the connected mode.

Scanning Procedure

A device performing scanning, that is, a scanning device performs ascanning procedure to listen to undirected broadcasting of user datafrom advertising devices using an advertising physical channel.

The scanning device transmits a scan request to an advertising devicethrough an advertising physical channel in order to request additionaldata from the advertising device. The advertising device transmits ascan response as a response with respect to the scan request, byincluding additional user data which has requested by the scanningdevice through an advertising physical channel.

The scanning procedure may be used while being connected to other BLEdevice in the BLE piconet.

If the scanning device is in an initiator mode in which the scanningdevice may receive an advertising event and initiates a connectionrequest. The scanning device may transmit a connection request to theadvertising device through the advertising physical channel to start aBluetooth connection with the advertising device.

When the scanning device transmits a connection request to theadvertising device, the scanning device stops the initiator modescanning for additional broadcast and enters the connected mode.

Discovering Procedure

Devices available for Bluetooth communication (hereinafter, referred toas “Bluetooth devices”) perform an advertising procedure and a scanningprocedure in order to discover devices located nearby or in order to bediscovered by other devices within a given area.

The discovering procedure is performed asymmetrically. A Bluetoothdevice intending to discover other device nearby is termed a discoveringdevice, and listens to discover devices advertising an advertising eventthat may be scanned. A Bluetooth device which may be discovered by otherdevice and available to be used is termed a discoverable device andpositively broadcasts an advertising event such that it may be scannedby other device through an advertising (broadcast) physical channel.

Both the discovering device and the discoverable device may have alreadybeen connected with other Bluetooth devices in a piconet.

Connecting Procedure

A connecting procedure is asymmetrical, and requests that, while aspecific Bluetooth device is performing an advertising procedure,another Bluetooth device should perform a scanning procedure.

That is, an advertising procedure may be aimed, and as a result, onlyone device may response to the advertising. After a connectableadvertising event is received from an advertising device, a connectingrequest may be transmitted to the advertising device through anadvertising (broadcast) physical channel to initiate connection.

Hereinafter, operational states, that is, an advertising state, ascanning state, an initiating state, and a connection state, in the BLEtechnology will be briefly described.

Advertising State

A link layer (LL) enters an advertising state according to aninstruction from a host (stack). In a case in which the LL is in theadvertising state, the LL transmits an advertising packet data unit(PDU) in advertising events.

Each of the advertising events include at least one advertising PDU, andthe advertising PDU is transmitted through an advertising channel indexin use. After the advertising PDU is transmitted through an advertisingchannel index in use, the advertising event may be terminated, or in acase in which the advertising device may need to secure a space forperforming other function, the advertising event may be terminatedearlier.

Scanning State

The LL enters the scanning state according to an instruction from thehost (stack). In the scanning state, the LL listens to advertisingchannel indices.

The scanning state includes two types: passive scanning and activescanning. Each of the scanning types is determined by the host.

Time for performing scanning or an advertising channel index are notdefined.

During the scanning state, the LL listens to an advertising channelindex in a scan window duration. A scan interval is defined as aninterval between start points of two continuous scan windows.

When there is no collision in scheduling, the LL should listen in orderto complete all the scan intervals of the scan window as instructed bythe host. In each scan window, the LL should scan other advertisingchannel index. The LL uses every available advertising channel index.

In the passive scanning, the LL only receives packets and cannottransmit any packet.

In the active scanning, the LL performs listening in order to be reliedon an advertising PDU type for requesting advertising PDUs andadvertising device-related supplemental information from the advertisingdevice.

Initiating State

The LL enters the initiating state according to an instruction from thehost (stack).

When the LL is in the initiating state, the LL performs listening onadvertising channel indices.

During the initiating state, the LL listens to an advertising channelindex during the scan window interval.

Connection State

When the device performing a connection state, that is, when theinitiating device transmits a CONNECT_REQ PDU to the advertising deviceor when the advertising device receives a CONNECT_REQ PDU from theinitiating device, the LL enters a connection state.

It is considered that a connection is generated after the LL enters theconnection state. However, it is not necessary to consider that theconnection should be established at a point in time at which the LLenters the connection state. The only difference between a newlygenerated connection and an already established connection is a LLconnection supervision timeout value.

When two devices are connected, the two devices play different roles.

An LL serving as a master is termed a master, and an LL serving as aslave is termed a slave. The master adjusts a timing of a connectingevent, and the connecting event refers to a point in time at which themaster and the slave are synchronized.

Hereinafter, packets defined in an Bluetooth interface will be brieflydescribed. BLE devices use packets defined as follows.

Packet Format

The LL has only one packet format used for both an advertising channelpacket and a data channel packet.

Each packet includes four fields of a preamble, an access address, aPDU, and a CRC.

When one packet is transmitted in an advertising physical channel, thePDU may be an advertising channel PDU, and when one packet istransmitted in a data physical channel, the PDU may be a data channelPDU.

Advertising Channel PDU

An advertising channel PDU has a 16-bit header and payload havingvarious sizes.

A PDU type field of the advertising channel PDU included in the heaterindicates PDU types defined in Table 3 below.

TABLE 3 PDU Type Packet Name 0000 ADV_IND 0001 ADV_DIRECT_IND 0010ADV_NONCONN_IND 0011 SCAN_REQ 0100 SCAN_RSP 0101 CONNECT_REQ 0110ADV_SCAN_IND 0111-1111 Reserved

Advertising PDU The following advertising channel PDU types are termedadvertising PDUs and used in a specific event.

ADV_IND: Connectable undirected advertising event

ADV_DIRECT_IND: Connectable directed advertising event

ADV_NONCONN_IND: Unconnectable undirected advertising event

ADV_SCAN_IND: Scannable undirected advertising event

The PDUs are transmitted from the LL in an advertising state, andreceived by the LL in a scanning state or in an initiating state.

Scanning PDU

The following advertising channel DPU types are termed scanning PDUs andare used in a state described hereinafter.

SCAN_REQ: Transmitted by the LL in a scanning state and received by theLL in an advertising state.

SCAN_RSP: Transmitted by the LL in the advertising state and received bythe LL in the scanning state.

Initiating PDU

The following advertising channel PDU type is termed an initiating PDU.

CONNECT_REQ: Transmitted by the LL in the initiating state and receivedby the LL in the advertising state.

Data Channel PDU

The data channel PDU may include a message integrity check (MIC) fieldhaving a 16-bit header and payload having various sizes.

The procedures, states, and packet formats in the BLE technologydiscussed above may be applied to perform the methods proposed in thepresent disclosure.

Referring to FIG. 4 a, The load (455) may correspond to a battery. Thebattery may store energy by using the power that is being outputted fromthe power pick-up unit (210). Meanwhile, the battery is not mandatorilyrequired to be included in the mobile device (450). For example, thebattery may be provided as a detachable external feature. As anotherexample, the wireless power receiver may include an operating means thatmay execute diverse functions of the electronic device instead of thebattery.

As shown in the drawing, although the mobile device (450) is illustratedto be included in the wireless power receiver (200) and the base station(400) is illustrated to be included in the wireless power transmitter(100), in a broader meaning, the wireless power receiver (200) may beidentified (or regarded) as the mobile device (450), and the wirelesspower transmitter (100) may be identified (or regarded) as the basestation (400).

When the communication/control circuit 120 and the communication/controlcircuit 220 include Bluetooth or Bluetooth LE as an OB communicationmodule or a short-range communication module in addition to the IBcommunication module, the wireless power transmitter 100 including thecommunication/control circuit 120 and the wireless power receiver 200including the communication/control circuit 220 may be represented by asimplified block diagram as shown in FIG. 4 c.

FIG. 4c is a block diagram illustrating a wireless power transfer systemusing BLE communication according to an example.

Referring to FIG. 4 c, the wireless power transmitter 100 includes apower conversion circuit 110 and a communication/control circuit 120.The communication/control circuit 120 includes an in-band communicationmodule 121 and a BLE communication module 122.

Meanwhile, the wireless power receiver 200 includes a power pickupcircuit 210 and a communication/control circuit 220. Thecommunication/control circuit 220 includes an in-band communicationmodule 221 and a BLE communication module 222.

In one aspect, the BLE communication modules 122 and 222 perform thearchitecture and operation according to FIG. 4 b. For example, the BLEcommunication modules 122 and 222 may be used to establish a connectionbetween the wireless power transmitter 100 and the wireless powerreceiver 200 and exchange control information and packets necessary forwireless power transfer.

In another aspect, the communication/control circuit 120 may beconfigured to operate a profile for wireless charging. Here, the profilefor wireless charging may be GATT using BLE transmission.

FIG. 4d is a block diagram illustrating a wireless power transfer systemusing BLE communication according to another example.

Referring to FIG. 4 d, the communication/control circuits 120 and 220respectively include only in-band communication modules 121 and 221, andthe BLE communication modules 122 and 222 may be provided to beseparated from the communication/control circuits 120 and 220.

Hereinafter, the coil or coil unit includes a coil and at least onedevice being approximate to the coil, and the coil or coil unit may alsobe referred to as a coil assembly, a coil cell, or a cell.

FIG. 5 is a state transition diagram for describing a wireless powertransfer procedure.

Referring to FIG. 5, the power transfer (or transfer) from the wirelesspower transmitter to the wireless power receiver according to anexemplary embodiment of the present disclosure may be broadly dividedinto a selection phase (510), a ping phase (520), an identification andconfiguration phase (530), a negotiation phase (540), a calibrationphase (550), a power transfer phase (560), and a renegotiation phase(570).

If a specific error or a specific event is detected when the powertransfer is initiated or while maintaining the power transfer, theselection phase (510) may include a shifting phase (or step)—referencenumerals S502, S504, S508, S510, and S512. Herein, the specific error orspecific event will be specified in the following description.Additionally, during the selection phase (510), the wireless powertransmitter may monitor whether or not an object exists on an interfacesurface. If the wireless power transmitter detects that an object isplaced on the interface surface, the process step may be shifted to theping phase (520). During the selection phase (510), the wireless powertransmitter may transmit an analog ping having a power signal(or apulse) corresponding to an extremely short duration, and may detectwhether or not an object exists within an active area of the interfacesurface based on a current change in the transmitting coil or theprimary coil.

In case an object is sensed (or detected) in the selection phase (510),the wireless power transmitter may measure a quality factor of awireless power resonance circuit (e.g., power transfer coil and/orresonance capacitor). According to the exemplary embodiment of thepresent disclosure, during the selection phase (510), the wireless powertransmitter may measure the quality factor in order to determine whetheror not a foreign object exists in the charging area along with thewireless power receiver. In the coil that is provided in the wirelesspower transmitter, inductance and/or components of the series resistancemay be reduced due to a change in the environment, and, due to suchdecrease, a value of the quality factor may also be decreased. In orderto determine the presence or absence of a foreign object by using themeasured quality factor value, the wireless power transmitter mayreceive from the wireless power receiver a reference quality factorvalue, which is measured in advance in a state where no foreign objectis placed within the charging area. The wireless power transmitter maydetermine the presence or absence of a foreign object by comparing themeasured quality factor value with the reference quality factor value,which is received during the negotiation phase (540). However, in caseof a wireless power receiver having a low reference quality factorvalue—e.g., depending upon its type, purpose, characteristics, and soon, the wireless power receiver may have a low reference quality factorvalue—in case a foreign object exists, since the difference between thereference quality factor value and the measured quality factor value issmall (or insignificant), a problem may occur in that the presence ofthe foreign object cannot be easily determined. Accordingly, in thiscase, other determination factors should be further considered, or thepresent or absence of a foreign object should be determined by usinganother method.

According to another exemplary embodiment of the present disclosure, incase an object is sensed (or detected) in the selection phase (510), inorder to determine whether or not a foreign object exists in thecharging area along with the wireless power receiver, the wireless powertransmitter may measure the quality factor value within a specificfrequency area (e.g., operation frequency area). In the coil that isprovided in the wireless power transmitter, inductance and/or componentsof the series resistance may be reduced due to a change in theenvironment, and, due to such decrease, the resonance frequency of thecoil of the wireless power transmitter may be changed (or shifted). Morespecifically, a quality factor peak frequency that corresponds to afrequency in which a maximum quality factor value is measured within theoperation frequency band may be moved (or shifted).

In the ping phase (520), if the wireless power transmitter detects thepresence of an object, the transmitter activates (or Wakes up) areceiver and transmits a digital ping for identifying whether or not thedetected object corresponds to the wireless power receiver. During theping phase (520), if the wireless power transmitter fails to receive aresponse signal for the digital ping—e.g., a signal intensitypacket—from the receiver, the process may be shifted back to theselection phase (510). Additionally, in the ping phase (520), if thewireless power transmitter receives a signal indicating the completionof the power transfer—e.g., charging complete packet—from the receiver,the process may be shifted back to the selection phase (510).

If the ping phase (520) is completed, the wireless power transmitter mayshift to the identification and configuration phase (530) foridentifying the receiver and for collecting configuration and statusinformation.

In the identification and configuration phase (530), if the wirelesspower transmitter receives an unwanted packet (i.e., unexpected packet),or if the wireless power transmitter fails to receive a packet during apredetermined period of time (i.e., out of time), or if a packettransmission error occurs (i.e., transmission error), or if a powertransfer contract is not configured (i.e., no power transfer contract),the wireless power transmitter may shift to the selection phase (510).

The wireless power transmitter may confirm (or verify) whether or notits entry to the negotiation phase (540) is needed based on aNegotiation field value of the configuration packet, which is receivedduring the identification and configuration phase (530). Based on theverified result, in case a negotiation is needed, the wireless powertransmitter enters the negotiation phase (540) and may then perform apredetermined FOD detection procedure. Conversely, in case a negotiationis not needed, the wireless power transmitter may immediately enter thepower transfer phase (560).

In the negotiation phase (540), the wireless power transmitter mayreceive a Foreign Object Detection (FOD) status packet that includes areference quality factor value. Or, the wireless power transmitter mayreceive an FOD status packet that includes a reference peak frequencyvalue. Alternatively, the wireless power transmitter may receive astatus packet that includes a reference quality factor value and areference peak frequency value. At this point, the wireless powertransmitter may determine a quality coefficient threshold value for FOdetection based on the reference quality factor value. The wirelesspower transmitter may determine a peak frequency threshold value for FOdetection based on the reference peak frequency value.

The wireless power transmitter may detect the presence or absence of anFO in the charging area by using the determined quality coefficientthreshold value for FO detection and the currently measured qualityfactor value (i.e., the quality factor value that was measured beforethe ping phase), and, then, the wireless power transmitter may controlthe transmitted power in accordance with the FO detection result. Forexample, in case the FO is detected, the power transfer may be stopped.However, the present disclosure will not be limited only to this.

The wireless power transmitter may detect the presence or absence of anFO in the charging area by using the determined peak frequency thresholdvalue for FO detection and the currently measured peak frequency value(i.e., the peak frequency value that was measured before the pingphase), and, then, the wireless power transmitter may control thetransmitted power in accordance with the FO detection result. Forexample, in case the FO is detected, the power transfer may be stopped.However, the present disclosure will not be limited only to this.

In case the FO is detected, the wireless power transmitter may return tothe selection phase (510). Conversely, in case the FO is not detected,the wireless power transmitter may proceed to the calibration phase(550) and may, then, enter the power transfer phase (560). Morespecifically, in case the FO is not detected, the wireless powertransmitter may determine the intensity of the received power that isreceived by the receiving end during the calibration phase (550) and maymeasure power loss in the receiving end and the transmitting end inorder to determine the intensity of the power that is transmitted fromthe transmitting end. In other words, during the calibration phase(550), the wireless power transmitter may estimate the power loss basedon a difference between the transmitted power of the transmitting endand the received power of the receiving end. The wireless powertransmitter according to the exemplary embodiment of the presentdisclosure may calibrate the threshold value for the FOD detection byapplying the estimated power loss.

In the power transfer phase (560), in case the wireless powertransmitter receives an unwanted packet (i.e., unexpected packet), or incase the wireless power transmitter fails to receive a packet during apredetermined period of time (i.e., time-out), or in case a violation ofa predetermined power transfer contract occurs (i.e., power transfercontract violation), or in case charging is completed, the wirelesspower transmitter may shift to the selection phase (510).

Additionally, in the power transfer phase (560), in case the wirelesspower transmitter is required to reconfigure the power transfer contractin accordance with a status change in the wireless power transmitter,the wireless power transmitter may shift to the renegotiation phase(570). At this point, if the renegotiation is successfully completed,the wireless power transmitter may return to the power transfer phase(560).

In this embodiment, the calibration step 550 and the power transferphase 560 are divided into separate steps, but the calibration step 550may be integrated into the power transfer phase 560. In this case,operations in the calibration step 550 may be performed in the powertransfer phase 560.

The above-described power transfer contract may be configured based onthe status and characteristic information of the wireless powertransmitter and receiver. For example, the wireless power transmitterstatus information may include information on a maximum amount oftransmittable power, information on a maximum number of receivers thatmay be accommodated, and so on. And, the receiver status information mayinclude information on the required power, and so on.

FIG. 6 shows a power control method according to an exemplary embodimentof the present disclosure.

As shown in FIG. 6, in the power transfer phase (560), by alternatingthe power transfer and/or reception and communication, the wirelesspower transmitter (100) and the wireless power receiver (200) maycontrol the amount (or size) of the power that is being transferred. Thewireless power transmitter and the wireless power receiver operate at aspecific control point. The control point indicates a combination of thevoltage and the electric current that are provided from the output ofthe wireless power receiver, when the power transfer is performed.

More specifically, the wireless power receiver selects a desired controlpoint, a desired output current/voltage, a temperature at a specificlocation of the mobile device, and so on, and additionally determines anactual control point at which the receiver is currently operating. Thewireless power receiver calculates a control error value by using thedesired control point and the actual control point, and, then, thewireless power receiver may transmit the calculated control error valueto the wireless power transmitter as a control error packet.

Also, the wireless power transmitter may configure/control a newoperating point—amplitude, frequency, and duty cycle—by using thereceived control error packet, so as to control the power transfer.Therefore, the control error packet may be transmitted/received at aconstant time interval during the power transfer phase, and, accordingto the exemplary embodiment, in case the wireless power receiverattempts to reduce the electric current of the wireless powertransmitter, the wireless power receiver may transmit the control errorpacket by setting the control error value to a negative number. And, incase the wireless power receiver intends to increase the electriccurrent of the wireless power transmitter, the wireless power receivertransmit the control error packet by setting the control error value toa positive number. During the induction mode, by transmitting thecontrol error packet to the wireless power transmitter as describedabove, the wireless power receiver may control the power transfer.

In the resonance mode, which will hereinafter be described in detail,the device may be operated by using a method that is different from theinduction mode. In the resonance mode, one wireless power transmittershould be capable of serving a plurality of wireless power receivers atthe same time. However, in case of controlling the power transfer justas in the induction mode, since the power that is being transferred iscontrolled by a communication that is established with one wirelesspower receiver, it may be difficult to control the power transfer ofadditional wireless power receivers. Therefore, in the resonance modeaccording to the present disclosure, a method of controlling the amountof power that is being received by having the wireless power transmittercommonly transfer (or transmit) the basic power and by having thewireless power receiver control its own resonance frequency.Nevertheless, even during the operation of the resonance mode, themethod described above in FIG. 6 will not be completely excluded. And,additional control of the transmitted power may be performed by usingthe method of FIG. 6.

FIG. 7 is a block diagram of a wireless power transmitter according toanother exemplary embodiment of the present disclosure. This may belongto a wireless power transfer system that is being operated in themagnetic resonance mode or the shared mode. The shared mode may refer toa mode performing a several-for-one (or one-to-many) communication andcharging between the wireless power transmitter and the wireless powerreceiver. The shared mode may be implemented as a magnetic inductionmethod or a resonance method.

Referring to FIG. 7, the wireless power transmitter (700) may include atleast one of a cover (720) covering a coil assembly, a power adapter(730) supplying power to the power transmitter (740), a powertransmitter (740) transmitting wireless power, and a user interface(750) providing information related to power transfer processing andother related information. Most particularly, the user interface (750)may be optionally included or may be included as another user interface(750) of the wireless power transmitter (700).

The power transmitter (740) may include at least one of a coil assembly(760), an impedance matching circuit (770), an inverter (780), acommunication unit (790), and a control unit (710).

The coil assembly (760) includes at least one primary coil generating amagnetic field. And, the coil assembly (760) may also be referred to asa coil cell.

The impedance matching circuit (770) may provide impedance matchingbetween the inverter and the primary coil(s). The impedance matchingcircuit (770) may generate resonance from a suitable frequency thatboosts the electric current of the primary coil(s). In a multi-coilpower transmitter (740), the impedance matching circuit may additionallyinclude a multiplex that routes signals from the inverter to a subset ofthe primary coils. The impedance matching circuit may also be referredto as a tank circuit.

The impedance matching circuit (770) may include a capacitor, aninductor, and a switching device that switches the connection betweenthe capacitor and the inductor. The impedance matching may be performedby detecting a reflective wave of the wireless power that is beingtransferred (or transmitted) through the coil assembly (760) and byswitching the switching device based on the detected reflective wave,thereby adjusting the connection status of the capacitor or the inductoror adjusting the capacitance of the capacitor or adjusting theinductance of the inductor. In some cases, the impedance matching may becarried out even though the impedance matching circuit (770) is omitted.This specification also includes an exemplary embodiment of the wirelesspower transmitter (700), wherein the impedance matching circuit (770) isomitted.

The inverter (780) may convert a DC input to an AC signal. The inverter(780) may be operated as a half-bridge inverter or a full-bridgeinverter in order to generate a pulse wave and a duty cycle of anadjustable frequency. Additionally, the inverter may include a pluralityof stages in order to adjust input voltage levels.

The communication unit (790) may perform communication with the powerreceiver. The power receiver performs load modulation in order tocommunicate requests and information corresponding to the powertransmitter. Therefore, the power transmitter (740) may use thecommunication unit (790) so as to monitor the amplitude and/or phase ofthe electric current and/or voltage of the primary coil in order todemodulate the data being transmitted from the power receiver.

Additionally, the power transmitter (740) may control the output powerto that the data may be transferred through the communication unit (790)by using a Frequency Shift Keying (FSK) method, and so on.

The control unit (710) may control communication and power transfer (ordelivery) of the power transmitter (740). The control unit (710) maycontrol the power transfer by adjusting the above-described operatingpoint. The operating point may be determined by, for example, at leastany one of the operation frequency, the duty cycle, and the inputvoltage.

The communication unit (790) and the control unit (710) may each beprovided as a separate unit/device/chipset or may be collectivelyprovided as one unit/device/chipset.

FIG. 8 shows a wireless power receiver according to another exemplaryembodiment of the present disclosure. This may belong to a wirelesspower transfer system that is being operated in the magnetic resonancemode or the shared mode.

Referring to FIG. 8, the wireless power receiver (800) may include atleast one of a user interface (820) providing information related topower transfer processing and other related information, a powerreceiver (830) receiving wireless power, a load circuit (840), and abase (850) supporting and covering the coil assembly. Most particularly,the user interface (820) may be optionally included or may be includedas another user interface (820) of the wireless power receiver (800).

The power receiver (830) may include at least one of a power converter(860), an impedance matching circuit (870), a coil assembly (880), acommunication unit (890), and a control unit (810).

The power converter (860) may convert the AC power that is received fromthe secondary coil to a voltage and electric current that are suitablefor the load circuit. According to an exemplary embodiment, the powerconverter (860) may include a rectifier. The rectifier may rectify thereceived wireless power and may convert the power from an alternatingcurrent (AC) to a direct current (DC). The rectifier may convert thealternating current to the direct current by using a diode or atransistor, and, then, the rectifier may smooth the converted current byusing the capacitor and resistance. Herein, a full-wave rectifier, ahalf-wave rectifier, a voltage multiplier, and so on, that areimplemented as a bridge circuit may be used as the rectifier.Additionally, the power converter may adapt a reflected impedance of thepower receiver.

The impedance matching circuit (870) may provide impedance matchingbetween a combination of the power converter (860) and the load circuit(840) and the secondary coil. According to an exemplary embodiment, theimpedance matching circuit may generate a resonance of approximately 100kHz, which may reinforce the power transfer. The impedance matchingcircuit (870) may include a capacitor, an inductor, and a switchingdevice that switches the combination of the capacitor and the inductor.The impedance matching may be performed by controlling the switchingdevice of the circuit that configured the impedance matching circuit(870) based on the voltage value, electric current value, power value,frequency value, and so on, of the wireless power that is beingreceived. In some cases, the impedance matching may be carried out eventhough the impedance matching circuit (870) is omitted. Thisspecification also includes an exemplary embodiment of the wirelesspower receiver (200), wherein the impedance matching circuit (870) isomitted.

The coil assembly (880) includes at least one secondary coil, and,optionally, the coil assembly (880) may further include an elementshielding the metallic part of the receiver from the magnetic field.

The communication unit (890) may perform load modulation in order tocommunicate requests and other information to the power transmitter.

For this, the power receiver (830) may perform switching of theresistance or capacitor so as to change the reflected impedance.

The control unit (810) may control the received power. For this, thecontrol unit (810) may determine/calculate a difference between anactual operating point and a target operating point of the powerreceiver (830). Thereafter, by performing a request for adjusting thereflected impedance of the power transmitter and/or for adjusting anoperating point of the power transmitter, the difference between theactual operating point and the target operating point may beadjusted/reduced. In case of minimizing this difference, an optimalpower reception may be performed.

The communication unit (890) and the control unit (810) may each beprovided as a separate device/chipset or may be collectively provided asone device/chipset.

FIG. 9 shows a communication frame structure according to an exemplaryembodiment of the present disclosure. This may correspond to acommunication frame structure in a shared mode.

Referring to FIG. 9, in the shared mode, different forms of frames maybe used along with one another. For example, in the shared mode, aslotted frame having a plurality of slots, as shown in (A), and a freeformat frame that does not have a specified format, as shown in (B), maybe used. More specifically, the slotted frame corresponds to a frame fortransmitting short data packets from the wireless power receiver (200)to the wireless power transmitter (100). And, since the free formatframe is not configured of a plurality of slots, the free format framemay correspond to a frame that is capable of performing transmission oflong data packets.

Meanwhile, the slotted frame and the free format frame may be referredto other diverse terms by anyone skilled in the art. For example, theslotted frame may be alternatively referred to as a channel frame, andthe free format frame may be alternatively referred to as a messageframe.

More specifically, the slotted frame may include a sync patternindicating the starting point (or beginning) of a slot, a measurementslot, nine slots, and additional sync patterns each having the same timeinterval that precedes each of the nine slots.

Herein, the additional sync pattern corresponds to a sync pattern thatis different from the sync pattern that indicates the starting point ofthe above-described frame. More specifically, the additional syncpattern does not indicate the starting point of the frame but mayindicate information related to the neighboring (or adjacent) slots(i.e., two consecutive slots positioned on both sides of the syncpattern).

Among the nine slots, each sync pattern may be positioned between twoconsecutive slots. In this case, the sync pattern may provideinformation related to the two consecutive slots.

Additionally, the nine slots and the sync patterns being provided beforeeach of the nine slots may have the same time interval. For example, thenine slots may have a time interval of 50 ms. And, the nine syncpatterns may have a time length of 50 ms.

Meanwhile, the free format frame, as shown in (B) may not have aspecific format apart from the sync pattern indicating the startingpoint of the frame and the measurement slot. More specifically, the freeformat frame is configured to perform a function that is different fromthat of the slotted frame. For example, the free format frame may beused to perform a function of performing communication of long datapackets (e.g., additional owner information packets) between thewireless power transmitter and the wireless power receiver, or, in caseof a wireless power transmitter being configured of multiple coils, toperform a function of selecting any one of the coils.

Hereinafter, a sync pattern that is included in each frame will bedescribed in more detail with reference to the accompanying drawings.

FIG. 10 is a structure of a sync pattern according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 10, the sync pattern may be configured of a preamble,a start bit, a response field, a type field, an info field, and a paritybit. In FIG. 10, the start bit is illustrated as ZERO.

More specifically, the preamble is configured of consecutive bits, andall of the bits may be set to 0. In other words, the preamble maycorrespond to bits for matching a time length of the sync pattern.

The number of bits configuring the preamble may be subordinate to theoperation frequency so that the length of the sync pattern may be mostapproximate to 50 ms but within a range that does not exceed 50 ms. Forexample, in case the operation frequency corresponds to 100 kHz, thesync pattern may be configured of two preamble bits, and, in case theoperation frequency corresponds to 105 kHz, the sync pattern may beconfigured of three preamble bits.

The start bit may correspond to a bit that follows the preamble, and thestart bit may indicate ZERO. The ZERO may correspond to a bit thatindicates a type of the sync pattern. Herein, the type of sync patternsmay include a frame sync including information that is related to aframe, and a slot sync including information of the slot. Morespecifically, the sync pattern may be positioned between consecutiveframes and may correspond to a frame sync that indicate a start of theframe, or the sync pattern may be positioned between consecutive slotsamong a plurality of slots configuring the frame and may correspond to async slot including information related to the consecutive slots.

For example, in case the ZERO is equal to 0, this may indicate that thecorresponding slot is a slot sync that is positioned in-between slots.And, in case the ZERO is equal to 1, this may indicate that thecorresponding sync pattern is a frame sync being located in-betweenframes.

A parity bit corresponds to a last bit of the sync pattern, and theparity bit may indicate information on a number of bits configuring thedata fields (i.e., the response field, the type field, and the infofield) that are included in the sync pattern. For example, in case thenumber of bits configuring the data fields of the sync patterncorresponds to an even number, the parity bit may be set to when, and,otherwise (i.e., in case the number of bits corresponds to an oddnumber), the parity bit may be set to 0.

The response field may include response information of the wirelesspower transmitter for its communication with the wireless power receiverwithin a slot prior to the sync pattern. For example, in case acommunication between the wireless power transmitter and the wirelesspower receiver is not detected, the response field may have a value of‘00’. Additionally, if a communication error is detected in thecommunication between the wireless power transmitter and the wirelesspower receiver, the response field may have a value of ‘01’. Thecommunication error corresponds to a case where two or more wirelesspower receivers attempt to access one slot, thereby causing collision tooccur between the two or more wireless power receivers.

Additionally, the response field may include information indicatingwhether or not the data packet has been accurately received from thewireless power receiver. More specifically, in case the wireless powertransmitter has denied the data packet, the response field may have avalue of “10” (10— not acknowledge (NAK)). And, in case the wirelesspower transmitter has confirmed the data packet, the response field mayhave a value of “11” (11— acknowledge (ACK)).

The type field may indicate the type of the sync pattern. Morespecifically, in case the sync pattern corresponds to a first syncpattern of the frame (i.e., as the first sync pattern, in case the syncpattern is positioned before the measurement slot), the type field mayhave a value of ‘1’, which indicates a frame sync.

Additionally, in a slotted frame, in case the sync pattern does notcorrespond to the first sync pattern of the frame, the type field mayhave a value of ‘0’, which indicates a slot sync.

Moreover, the information field may determine the meaning of its valuein accordance with the sync pattern type, which is indicated in the typefield. For example, in case the type field is equal to 1 (i.e., in casethe sync pattern type indicates a frame sync), the meaning of theinformation field may indicate the frame type. More specifically, theinformation field may indicate whether the current frame corresponds toa slotted frame or a free-format frame. For example, in case theinformation field is given a value of ‘00’, this indicates that thecurrent frame corresponds to a slotted frame. And, in case theinformation field is given a value of ‘01’, this indicates that thecurrent frame corresponds to a free-format frame.

Conversely, in case the type field is equal to 0 (i.e., in case the syncpattern type indicates a slot sync), the information field may indicatea state of a next slot, which is positioned after the sync pattern. Morespecifically, in case the next slot corresponds to a slot that isallocated (or assigned) to a specific wireless power receiver, theinformation field is given a value of ‘00’. In case the next slotcorresponds to a slot that is locked, so as to be temporarily used bythe specific wireless power receiver, the information field is given avalue of ‘01’. Alternatively, in case the next slot corresponds to aslot that may be freely used by a random wireless power receiver, theinformation field is given a value of ‘10’.

FIG. 11 shows operation statuses of a wireless power transmitter and awireless power receiver in a shared mode according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 11, the wireless power receiver operating in theshared mode may be operated in any one of a selection phase (1100), anintroduction phase (1110), a configuration phase (1120), a negotiationphase (1130), and a power transfer phase (1140).

Firstly, the wireless power transmitter according to the exemplaryembodiment of the present disclosure may transmit a wireless powersignal in order to detect the wireless power receiver. Morespecifically, a process of detecting a wireless power receiver by usingthe wireless power signal may be referred to as an Analog ping.

Meanwhile, the wireless power receiver that has received the wirelesspower signal may enter the selection phase (1100). As described above,the wireless power receiver that has entered the selection phase (1100)may detect the presence or absence of an FSK signal within the wirelesspower signal.

In other words, the wireless power receiver may perform communication byusing any one of an exclusive mode and a shared mode in accordance withthe presence or absence of the FSK signal.

More specifically, in case the FSK signal is included in the wirelesspower signal, the wireless power receiver may operate in the sharedmode, and, otherwise, the wireless power receiver may operate in theexclusive mode.

In case the wireless power receiver operates in the shared mode, thewireless power receiver may enter the introduction phase (1110). In theintroduction phase (1110), the wireless power receiver may transmit acontrol information (CI) packet to the wireless power transmitter inorder to transmit the control information packet during theconfiguration phase, the negotiation phase, and the power transferphase. The control information packet may have a header and informationrelated to control. For example, in the control information packet, theheader may correspond to 0X53.

In the introduction phase (1110), the wireless power receiver performsan attempt to request a free slot for transmitting the controlinformation (CI) packet during the following configuration phase,negotiation phase, and power transfer phase. At this point, the wirelesspower receiver selects a free slot and transmits an initial CI packet.If the wireless power transmitter transmits an ACK as a response to thecorresponding CI packet, the wireless power receiver enters theconfiguration phase. If the wireless power transmitter transmits a NAKas a response to the corresponding CI packet, this indicates thatanother wireless power receiver is performing communication through theconfiguration and negotiation phase. In this case, the wireless powerreceiver re-attempts to perform a request for a free slot.

If the wireless power receiver receives an ACK as a response to the CIpacket, the wireless power receiver may determine the position of aprivate slot within the frame by counting the remaining sync slots up tothe initial frame sync. In all of the subsequent slot-based frames, thewireless power receiver transmits the CI packet through thecorresponding slot.

If the wireless power transmitter authorizes the entry of the wirelesspower receiver to the configuration phase, the wireless powertransmitter provides a locked slot series for the exclusive usage of thewireless power receiver. This may ensure the wireless power receiver toproceed to the configuration phase without any collision.

The wireless power receiver transmits sequences of data packets, such astwo identification data packets (IDHI and IDLO), by using the lockedslots. When this phase is completed, the wireless power receiver entersthe negotiation phase. During the negotiation state, the wireless powertransmitter continues to provide the locked slots for the exclusiveusage of the wireless power receiver. This may ensure the wireless powerreceiver to proceed to the negotiation phase without any collision.

The wireless power receiver transmits one or more negotiation datapackets by using the corresponding locked slot, and the transmittednegotiation data packet(s) may be mixed with the private data packets.Eventually, the corresponding sequence is ended (or completed) alongwith a specific request (SRQ) packet. When the corresponding sequence iscompleted, the wireless power receiver enters the power transfer phase,and the wireless power transmitter stops the provision of the lockedslots.

In the power transfer phase, the wireless power receiver performs thetransmission of a CI packet by using the allocated slots and thenreceives the power. The wireless power receiver may include a regulatorcircuit. The regulator circuit may be included in acommunication/control unit. The wireless power receiver mayself-regulate a reflected impedance of the wireless power receiverthrough the regulator circuit. In other words, the wireless powerreceiver may adjust the impedance that is being reflected for an amountof power that is requested by an external load. This may prevent anexcessive reception of power and overheating.

In the shared mode, (depending upon the operation mode) since thewireless power transmitter may not perform the adjustment of power as aresponse to the received CI packet, in this case, control may be neededin order to prevent an overvoltage state.

Hereinafter, authentication between a wireless power transmitter and awireless power receiver will be disclosed.

The wireless power transfer system using in-band communication may useUSB-C authentication. The authentication may include an authenticationof the wireless power transmitter that is performed by the wirelesspower receiver (i.e., PTx Authentication by PRx), and an authenticationof the wireless power receiver that is performed by the wireless powertransmitter (PRx Authentication by PTx).

FIG. 12 is a block diagram showing a wireless charging certificateformat according to an exemplary embodiment of the present disclosure.

Referring to FIG. 12, the wireless charging certificate format includesa Certificate Structure Version, a reserved field, PTx and leafindicators, a certificate type, a signature offset, a serial number, anissuer ID, a subject ID, a public key, and a signature.

The certificate type may, for example, by assigned with 3 bits, and thecertificate type may indicate that the corresponding certificate is anyone of a root certificate, an intermediate certificate, and a lastcertificate. And, the certificate type may also indicate that thecorresponding certificate is a certificate relating to a wireless powertransmitter or a wireless power receiver or all type.

For example, the certificate type is 3 bits and may indicate informationon a root certificate, manufacturer/secondary certificate, and productunit certificate (for the power transmitter). More specifically, acertificate type ‘001’b may indicate the root certificate, and ‘010’bmay indicate an intermediate certificate (manufacturer/secondaryCertificate), and ‘111’b may indicate a product unit certificate for thepower transmitter, which is a final certificate.

The wireless power transmitter may notify (or announce) whether or notit supports the authentication function to the wireless power receiverby using a capability packet (in case of an authentication of thewireless power transmitter by the wireless power receiver(authentication of PTx by PRx)). Meanwhile, the wireless power receivermay notify (or announce) whether or not it supports the authenticationfunction to the wireless power transmitter by using a capability packet(in case of an authentication of the wireless power receiver by thewireless power transmitter (authentication of PRx by PTx)). Hereinafter,a structure of indication information (a capability packet and aconfiguration packet) related to whether or not a device supports theauthentication function will be disclosed and described in detail.

FIG. 13 is a capability packet structure of a wireless power transmitteraccording to an exemplary embodiment of the present disclosure.

Referring to FIG. 13, a capability packet having a respective headervalue of 0X31 is assigned with 3 bytes. Herein, a first byte (B0)includes a power class and a guaranteed power value, a second byte (B1)includes a reserved field and a potential power field, and a third byte(B2) includes an Authentication Initiator (AI), an AuthenticationResponder (AR), a reserved field, a WPID, and a Not Res Sens field. Morespecifically, the Authentication Initiator (AI) is assigned with 1 bit.Herein, for example, if the value is equal to ‘1 b’, this may indicatethat the corresponding wireless power transmitter may operate as theauthentication initiator. Additionally, the Authentication Responder(AR) is also assigned with 1 bit. Herein, for example, if the value isequal to ‘1 b’, this may indicate that the corresponding wireless powertransmitter may operate as the authentication responder.

FIG. 14 is a configuration packet structure of a wireless power receiveraccording to an exemplary embodiment of the present disclosure.

Referring to FIG. 14, a capability packet having a respective headervalue of 0X51 is assigned with 5 bytes. Herein, a first byte (B0)includes a power class and a maximum power value, a second byte (B1)includes an AI, an AR, a reserved field, a third byte (B2) includes aProp, a reserved field, a ZERO field, and a Count field, a fourth value(B3) includes a Window size and a window offset, and a fifth byte (B4)includes a Neg field, a polarity field, a Depth field, an authenticationfield (Auth), and a reserved field. More specifically, theAuthentication Initiator (AI) is assigned with 1 bit. Herein, forexample, if the value is equal to ‘1 b’, this may indicate that thecorresponding wireless power receiver may operate as the authenticationinitiator. Additionally, the Authentication Responder (AR) is alsoassigned with 1 bit. Herein, for example, if the value is equal to ‘1b’, this may indicate that the corresponding wireless power receiver mayoperate as the authentication responder.

A message that is used during the authentication procedure is referredto as an authentication message. The authentication message is used forcarrying information related to authentication. Herein, 2 differenttypes of authentication messages exist. One type corresponds to anauthentication request, and another type corresponds to anauthentication response. The authentication request is transmitted bythe authentication initiator, and the authentication response istransmitted by the authentication responder. Both the wireless powertransmitter and the wireless power receiver may be the authenticationinitiator or the authentication responder. For example, in case thewireless power transmitter is the authentication initiator, the wirelesspower receiver becomes the authentication responder. And, in case thewireless power receiver is the authentication initiator, the wirelesspower transmitter becomes the authentication responder.

An authentication request message includes a GET_DIGESTS (i.e., 4bytes), a GET_CERTIFICATE (i.e., 8 bytes), and a CHALLENGE (i.e., 36bytes).

An authentication response message includes a DIGESTS (i.e., 4+32bytes), a CERTIFICATE (i.e., 4+certificate chain (3×512 bytes)=1,540bytes), a CHALLENGE_AUTH (i.e., 168 bytes), and an ERROR (i.e., 4bytes).

An authentication message may be referred to as an authentication packetand may also be referred to as authentication data or authenticationcontrol information. Additionally, messages, such as GET_DIGEST,DIGESTS, and so on, may also be referred to as a GET_DIGEST packet, aDIGEST packet, and so on.

FIG. 15 shows an application-level data stream between a wireless powertransmitter and a receiver according to an example.

Referring to FIG. 15, a data stream may include an auxiliary datacontrol (ADC) data packet and/or an auxiliary data transport (ADT) datapacket.

The ADC data packet is used to open a data stream. The ADC data packetmay indicate the type of a message included in a stream and the numberof data bytes. Meanwhile, the ADT data packet is sequences of dataincluding an actual message. An ADC/end data packet is used to indicatethe end of the stream. For example, the maximum number of data bytes ina data transport stream may be limited to 2047.

ACK or NAC (NACK) is used to indicate whether the ADC data packet andthe ADT data packet are normally received. Control information necessaryfor wireless charging such as a control error packet (CE) or DSR may betransmitted between transmission timings of the ADC data packet and theADT data packet.

Using this data stream structure, authentication related information orother application level information may be transmitted and receivedbetween the wireless power transmitter and the wireless power receiver.

Hereinafter, the present document describes in detail a wireless powertransmitter 100 (Power transmitter: PTx) and method and a wireless powerreceiver 200 (Power receiver: PRx) and method for generating a mutuallyauthenticated BLE link.

In this specification, the Qi standard of WPC can be exemplified as astandard technology, the technical idea of the present document is toinclude embodiments of the wireless power transmitter 100 and method,and the wireless power receiver 200 and method based on the Qi standardas well as other standards.

Short-range communication, in particular, the core spec of BluetoothSpecification V4.0 can be divided into BR/EDR (Basic Rate/Enhanced DataRate) and LE (Low Energy). Of these, BR/EDR is a wireless communicationtechnology that has a dominant position in the short-range WPANtechnology and has been applied to many products. Meanwhile, BluetoothLow Energy (hereinafter referred to as BLE) is a technology announcedafter the Bluetooth standard document V4.0 and is designed with the goalof higher energy efficiency compared to the existing Bluetooth BR/EDR.

The wireless charging method includes a magnetic induction method usingthe magnetic induction phenomenon between the primary coil and thesecondary coil, and a magnetic resonance method in which magneticresonance is achieved using a frequency of several tens of kHz toseveral MHz bands to transmit power. The wireless charging standard forthe magnetic resonance method is led by a council called A4WP, and themagnetic induction method is led by the Wireless Power Consortium (WPC).

According to the WPC standard, the wireless power transmitter 100 andthe receiver are designed to exchange various status information andcommands related to the wireless charging system using in-bandcommunication. However, since in-band communication is not a systemdesigned specifically for communication, it is not suitable forhigh-speed, large-capacity information exchange and exchange of variousinformation. Therefore, a method for exchanging information related to awireless charging system by combining another wireless communicationsystem (i.e., an out-band communication system) with the existingin-band communication is being discussed. Out-band communicationincludes, for example, NFC and Bluetooth Low Energy (BLE) communication.BLE is one of the representative out-band communication technologies forwireless charging, and has advantages such as a faster transmissionspeed compared to the existing in-band communication channel and aconvenient data transmission method based on GATT.

In the case of BLE, before a device-to-device connection is established,a process of authenticating whether the device to be connected iscorrect is performed through a numeric key entry (passkey entry) ornumeric comparison on a screen output. If this process is not performedproperly, it is classified as an unauthenticated link, and it does notguarantee that it is connected to the intended device.

The wireless power transmitter 100 and the wireless power receiver 200exchange important and various information related to wireless powertransmission. In particular, the highest level of security is requiredbecause parameter information directly related to wireless powertransmission can cause damage to property and human life if manipulated.Therefore, when the above parameter information is transmitted throughout-band communication such as BLE, an authenticated link must be used.

For example, the passkey entry/numeric comparison method used forauthentication in BLE is available only in devices that support keyboardinput or display output, but, currently, the wireless power transmitter100 and the wireless power receiver 200 distributed in the market do notsupport this in many cases. That is, it is difficult to create anauthenticated BLE link for all devices.

Therefore, by generating an authenticated BLE link between the low-specwireless power transmitter 100 or the wireless power receiver 200 thatdoes not have a user input interface such as touch display output,keyboard input function, a wireless power transmitter 100 and method forenhancing security, and a wireless power receiver 200 and method arerequired.

According to an aspect of the present document, a wireless powertransmitter 100 and method for establishing an authenticated BLE linkbased on timing, and a wireless power receiver 200 and method areprovided.

According to another aspect of the present document, provided are awireless power transmitter 100 and method, and a wireless power receiver200 and method for performing an existing authentication process basedon an elliptic curve Diffie Hellman (ECDH) public key exchange method.

According to another aspect of the present document, provided are awireless power transmitter 100 and method, and a wireless power receiver200 and method for performing ECDH public key exchange in a situationwhere mutual authentication is completed.

According to another aspect of the present document, a wireless powertransmitter 100 and method, and a wireless power receiver 200 and methodfor generating a mutually authenticated BLE link are provided.

FIG. 16 is a flowchart illustrating a method of establishing anauthenticated link (authenticated BLE link) based on timing according toan embodiment. Meanwhile, the PTx 100 shown in FIG. 16 means thewireless power transmitter 100, and the PRx 200 means the wireless powerreceiver 200.

The PTx 100 in the embodiment according to FIG. 16 corresponds to thewireless power transmission device 100 or the wireless power transceiveror power transmission unit disclosed in FIGS. 1 to 15. Accordingly, theoperation of the wireless power transmitter 100 in this embodiment isimplemented by one or a combination of two or more of each component ofthe wireless power transmitter 100 in FIGS. 1 to 15. For example, theout-band (Bluetooth) communication module, the in-band communicationmodule, and the control unit according to FIG. 16 may be thecommunication/control unit 120 or may be included in thecommunication/control unit 120. Alternatively, the PTx BLE 100 aaccording to FIG. 16 may be the BLE communication module 122 of FIG. 4Cor 4D, the PTx in-band communication module according to FIG. 16 may bethe in-band communication module 121 of FIG. 4C or 4D.

For example, driving of the authentication permission period andoperation of the timer according to FIG. 16, exchange of connectionrequests, exchange of packets, etc. may be performed by thecommunication/control unit 120.

The PRx 200 in the embodiment according to FIG. 16 corresponds to awireless power reception device or a wireless power receiver or a powerreception unit disclosed in FIGS. 1 to 15. Accordingly, the operation ofthe PRx 200 in the present embodiment is implemented by one or acombination of two or more of each component of the wireless powerreceiver 200 in FIGS. 1 to 15. For example, the out-band (Bluetooth)communication module, the in-band communication module, and the controlunit according to FIG. 16 may be the communication/control unit 220 ormay be included in the communication/control unit 220. Alternatively,the PRx BLE 200 a according to FIG. 16 may be the BLE communicationmodule 222 of FIG. 4C or 4D, the PRx in-band communication moduleaccording to FIG. 16 may be the in-band communication module 221 of FIG.4C or 4D.

For example, driving of the authentication permission period andoperation of the timer according to FIG. 16, exchange of connectionrequests, exchange of packets, etc. may be performed by thecommunication/control unit 220.

Referring to FIG. 16, a method of initiating an authenticated BLE linkgeneration procedure based on timing according to an embodiment isperformed using a wireless power transmitter 100 and a wireless powerreceiver 200.

As shown, the wireless power transmitter 100 and the wireless powerreceiver 200 can communicate with each other through in-bandcommunication as well as each of the out-band communication modules (PTxBLE, PRx BLE) 100 a, 200 a is provided. As out-band communication, nearfield communication (NFC), Wi-Fi, and short-range wireless communicationsuch as Bluetooth may be used. First, the wireless power transmitter 100and the wireless power receiver 200 perform in-band communication andthen switch to out-band communication (or handover). When out-bandcommunication is switched, communication is performed between theout-band communication module of the wireless power transmitter 100(hereinafter referred to as ‘wireless power transmitter 100 BLE’ or ‘PTxBLE’, 100 a) and the out-band communication module of the wireless powerreceiver 200 (hereinafter referred to as ‘wireless power receiver 200BLE’ or ‘PRx BLE’, 200 a).

In this case, the wireless power transmitter 100 and/or the wirelesspower receiver 200 may provide a user interface related to informationfor a procedure for generating an authenticated link for charging.

This embodiment discloses a method for initiating the BLE link procedureas an authenticated link for charging between the wireless powertransmitter 100 and the wireless power receiver 200 without a separatedisplay output/keyboard input function, generating an authenticated linkby utilizing the timing at which the wireless power transmitter 100 andthe wireless power receiver 200 detect each other (Timing-basedauthenticated link establishment).

As shown, the in-band communication module of the wireless powertransmitter 100 and the in-band communication module of the wirelesspower receiver 200 sequentially exchange a signal strength packet, anidentification packet, a configuration packet, and the like, afterexchanging out-band information (OOB information) in the last packet,handover may be performed through out of band communication. That is,the authenticated link may be generated using out-band communication asa communication channel.

The wireless power transmitter 100 and the wireless power receiver 200may transmit a connection request and a message for link creation toeach other in order to initiate an authenticated link creationprocedure. At this time, in order to prevent a connection with anunauthenticated device (A), the wireless power transmitter 100 and thewireless power receiver 200 according to this embodiment are driven toinitiate a procedure for generating an authenticated link for chargingby only accepting a connect request received within a predeterminedauthentication accept period.

In other words, the wireless power transmitter 100 and the wirelesspower receiver 200 are preset or systematized to set a predeterminedperiod as the authentication permission period, and is configured toaccept only connection requests received within the authenticationpermission period, and it is configured to ignore other connectionrequests outside the authentication permission period. In this case, fora connection request other than the authentication permission period,information may be exchanged on an error code and permission.

As shown in FIG. 16, in the wireless power transmitter 100 and thewireless power receiver 200 according to an embodiment, theauthentication permission time may be calculated from the last packetexchange time by in-band communication. For example, after exchange ofout-band information as the last packet by in-band communication, apredetermined period range may be configured as an authenticationpermission time.

This embodiment may also be applied to establishing an authenticatedlink in out-band communication between the wireless power transmitter100 in the form of a sound bar and the wireless power receiver 200 inthe form of a TV.

On the other hand, in the authentication link generation method based onthe mutual detection timing of the wireless power transmitter 100 andthe wireless power receiver 200 according to the present embodiment, asdescribed above, an authenticated link can also be created between thewireless power transmitter 100 and the wireless power receiver 200 thatdo not have a separate display output/keyboard input function. On theother hand, when the attack device (A) is in very close proximity to thewireless power receiver 200 (for example, a slot next to the wirelesspower receiver 200 on the charging pad), communication informationbetween the wireless power transmitter 100 and the wireless powerreceiver 200 may be leaked to the attack device A. That is, there is arisk that the authentication permission timing is exposed to the attackdevice (A).

Hereinafter, an embodiment for solving the above risk will be describedin detail.

WPC authentication is performed through an elliptic curve-basedcertificate. On the other hand, the WPC standard stipulates that theelliptic curve is used only for authentication, but the Elliptic CurveCryptography (ECC) standard defines not only authentication but alsoencryption/decryption. In this embodiment, by using this, the wirelesspower communication device and the wireless power receiving device 200securely share secret information through in-band communication, andthen this value can be used for BLE pairing to create an authenticatedlink.

In this case, the ECC standard assumes that the two devices of thewireless power transmitter 100 and the wireless power receiver 200 knoweach other's public key for encryption/decryption. In order to applythis to the authentication of wireless power transmission technology, aseparate key exchange protocol should be defined in the WPC standard.This is because the public key is an ephemeral key different from thepublic key of the certificate.

FIG. 17a is a flowchart of an authentication process by Qiauthentication according to an example, and FIG. 17b is a diagramillustrating a packet format of the authentication response message(CHALLANGE_AUTH) of FIG. 17 a, respectively.

The authentication procedure introduced as an example in FIG. 17 is aprocess in which a device as an authentication initiator authenticates adevice as an authentication responder.

First, the authentication initiator exchangesGET_CERTIFICATE/CERTIFICATE messages with the authentication responderafter confirming that the peer device can perform authentication. Theauthentication initiator verifies the validity of the certificatereceived from the authentication responder.

After that, the authentication initiator sends a CHALLENGE message tothe authentication responder, the responder transmits a CHALLANGE_AUTHmessage signed with its own private key to the initiator. Accordingly,the initiator verifies the CHALLANGE_AUTH message sent by the responderusing the public key of the previously received certificate. If theCHALLANGE_AUTH is valid, the initiator completes authentication to theresponder.

FIGS. 18a and 18b are block diagrams illustrating an Elliptic CurveIntegrated Encryption Scheme according to an example.

An ECC-based encryption/decryption process is introduced as an exampleby way of FIG. 18. The illustrated process proceeds on the premise thatthe public key of the counterpart device is possessed. As describedabove, the public key here is different from the public key included inthe exchanged certificate. The key of the certificate is used only whengenerating a signature value through the ECDSA algorithm. The public keymentioned here is used when encrypting data based on the Diffie HellmanKey Agreement. For security, a new ephemeral key is generated everytime.

Hereinafter, based on the examples disclosed in FIGS. 17 and 18,respectively, an embodiment of a public key exchange method between thewireless power transmitter 100 and the wireless power receiver 200 andan embodiment of a method of applying the secret information (secret)exchanged by in-band communication to BLE will be described in detail.

Hereinafter, the wireless power transmitter 100 and the wireless powerreceiver 200 may be the authentication initiator 300 or theauthentication responder 400 to each other, respectively. For example,when the wireless power transmitter 100 is the authentication initiator300, the wireless power receiver 200 becomes the authenticationresponder 400, and on the contrary, when the wireless power receiver 200is the authentication initiator 300, the wireless power transmitter 100becomes the authentication responder 400.

Hereinafter, the authentication initiator 300 disclosed in FIGS. 19 to20 optionally corresponds to the wireless power transmission device 100or the wireless power transceiver or the power transmission unitdisclosed in FIGS. 1 to 16, or it corresponds to the wireless powerreception device 200 or the wireless power receiver or the powerreception unit disclosed in FIGS. 1 to 16.

Conversely, when the authentication initiator 300 is a wireless powertransmission device 100 or a wireless power transceiver or a powertransmission unit disclosed in FIGS. 1 to 16, the authenticationresponder 400 disclosed in FIGS. 19 to 20 corresponds to the wirelesspower reception device 200 or the wireless power receiver or the powerreception unit disclosed in FIGS. 1 to 16. Similarly, when theauthentication initiator 300 is a wireless power reception device 200 ora wireless power receiver or a power reception unit disclosed in FIGS. 1to 16, it will correspond to the wireless power transmission device 100or the wireless power transceiver or power transmission unit disclosedin FIGS. 1 to 16.

FIG. 19a is a flowchart conceptually showing how to perform the existingauthentication process based on the Elliptic Curve Diffie Hellman (ECDH)public key exchange method according to an example, and FIG. 19b is adiagram illustrating a format of an authentication response message(CHALLANGE_AUTH) of FIG. 19 a, respectively.

This embodiment discloses a method for the wireless power receiver 200and the wireless power transmitter 100 to exchange a Diffie-Hellmanpublic key in an authentication phase.

Referring to FIG. 19 a, in this example, after handover to out-bandcommunication, the wireless power receiver 200 and the wireless powertransmitter 100 switch the relationship between the authenticationinitiator 300 and the authentication responder 400 with each other. Inaddition, the same switching process is repeatedly performed.

Referring to FIG. 19B, the responder 400 transmits an authenticationresponse message (CHALLENGE_AUTH) including the public key in responseto the request message (CHALLENGE) of the initiator 300.

At this time, since the Diffie Hellman key does not guaranteeauthentication, the authentication response message in this embodimentmay be using a certificate-based signature together.

Accordingly, iterative, when the relationship between the authenticationinitiator 300 and the authentication responder 400 is switched over, thewireless power transmitter 100 and the wireless power receiver 200exchange each other's public keys. Using the exchanged public key, thewireless power transmitter 100 and the wireless power receiver 200 maycreate an authenticated link. A detailed description thereof will begiven later.

FIG. 20a is a flowchart illustrating a method of performing ECDH publickey exchange in a situation where mutual authentication is completedaccording to another example, and FIG. 20b is a diagram illustrating aformat of a Public Key Request/Response Message of FIG. 20 a,respectively.

This embodiment discloses a method for exchanging a Diffie-Hellmanpublic key after the wireless power receiver 200 and the wireless powertransmitter 100 complete authentication and exchange certificates.

Referring to FIG. 20 a, in this embodiment, in a state where mutualauthentication has already been completed and certificate exchange ismade between each other, the authentication initiator 300 generates afirst public key and a first signature, a public key request messageincluding the first public key and the first signature is transmitted tothe authentication responder 400.

Accordingly, the authentication responder 400 receives the public keyrequest message from the authentication initiator 300, the firstsignature of the public key request message is verified based on thepublic key of the exchanged authentication initiator 300 certificate.After that, the authentication responder 400 generates a second publickey and a second signature, a public key response message including thesecond public key and the second signature is transmitted to theauthentication initiator 300.

The authentication initiator 300 receiving the public key responsemessage from the authentication responder 400 verifies the secondsignature based on the public key of the exchanged authenticationresponder 400 certificate, the wireless power transmitter 100 and thewireless power receiver 200 exchange a Diffie-Hellman public key. Usingthe exchanged public key, the wireless power transmitter 100 and thewireless power receiver 200 may create an authenticated link. A detaileddescription thereof will be given later.

In this embodiment, the authentication initiator 300 and theauthentication responder 400 may be in the format of a Public KeyRequest/Response Message for transmitting and receiving the formatdisclosed as an example shown in FIG. 20 b.

According to the above-described embodiment, the wireless power receiver200 and the wireless power transmitter 100 exchanging the Diffie-Hellmanpublic key may generate a mutually authenticated link (an authenticatedBLE link) using the Diffie-Hellman public key.

FIG. 21 shows a flowchart illustrating an existing method of creating aBLE link according to an example.

Referring to FIG. 21, by the existing method of creating a BLE linkaccording to an example, in the state in which the link layer connectionis established (LL connection), the authentication initiator 300 and theauthentication responder 400 made a pairing request/response(Pairing_Request/Response) after an optional security request(Security_Request) in Phase I and made pairing over SMP (SecureConnections) in Phase II.

After that, an encrypted connection is established with the exchange keygenerated in Phase II, and key distribution is performed between theauthentication initiator 300 and the authentication responder 400 inPhase III.

FIG. 22a and FIG. 22b are flowcharts illustrating a method of generatinga mutually authenticated BLE link using the exchanged public keyaccording to the embodiment of FIG. 19 or FIG. 20, respectively.

Hereinafter, the authentication initiator 300 disclosed in FIGS. 22a and22b optionally corresponds to the wireless power transmission device 100or the wireless power transceiver or the power transmission unitdisclosed in FIGS. 1 to 16, or it corresponds to the wireless powerreception device 200 or the wireless power receiver or the powerreception unit disclosed in FIGS. 1 to 16.

Conversely, when the authentication initiator 300 is the wireless powertransmission device 100 or the wireless power transceiver or powertransmission unit disclosed in FIGS. 1 to 16, the authenticationresponder 400 disclosed in FIGS. 22A and 22B corresponds to the wirelesspower reception device 200 or the wireless power transceiver or thepower reception unit disclosed in FIGS. 1 to 16. Likewise, when theauthentication initiator 300 is the wireless power reception device 200or the wireless power receiver or the power reception unit disclosed inFIGS. 1 to 16, it will correspond to the wireless power transmissiondevice 100 or the wireless power transceiver or power transmission unitdisclosed in FIGS. 1 to 16.

In this embodiment, the Diffie Hellman key (DHKey) may be generatedusing the public key exchanged through the embodiments according toFIGS. 19 to 20 described in detail above. Accordingly, in the presentembodiment, as shown in FIGS. 22A and 22B, unlike in the conventionalmethod of generating a BLE link, Phase I may be omitted.

At this time, since the present embodiment adopts the BLE 256-bitelliptic curve-based security system, it is compatible with the wirelesspower transmission system as it is. In particular, when the embodimentaccording to FIGS. 22A and 22B is applied to out-band communication ofWPC, the value of Iocap may be collectively set to NoInput/NoOutput.

Since all components or steps are not essential for the wireless powertransmission method and apparatus, or the reception apparatus and methodaccording to the embodiment of the present document described above, anapparatus and method for transmitting power wirelessly, or an apparatusand method for receiving power may be performed by including some or allof the above-described components or steps. In addition, theabove-described wireless power transmission apparatus and method, or theembodiment of the reception apparatus and method may be performed incombination with each other. In addition, each of the above-describedcomponents or steps is not necessarily performed in the order described,and it is also possible that the steps described later are performedbefore the steps described earlier.

The above description is merely illustrative of the technical idea ofthe present document, those of ordinary skill in the art to which thepresent document pertains will be able to make various modifications andvariations without departing from the essential characteristics of thepresent document. Accordingly, the embodiments of the present documentdescribed above may be implemented separately or in combination witheach other.

Accordingly, the embodiments disclosed in the present document are notintended to limit the technical spirit of the present document, but toexplain, and the scope of the technical spirit of the present documentis not limited by these embodiments. The protection scope of the presentdocument should be construed by the following claims, all technicalideas within the scope equivalent thereto should be construed as beingincluded in the scope of the present document.

1. A wireless power receiver comprising: a power pickup circuitconfigured to form magnetic coupling with a wireless power transmitterto receive wireless power from the wireless power transmitter; and acommunication/control circuit configured to perform at least one oftransmission control of the wireless power and transmission andreception of data based on communication with the wireless powertransmitter, wherein the communication/control circuit is configured toinitiate a creation process of an authenticated link for charging byaccepting only a connect request received within a predeterminedauthentication accept period.
 2. The wireless power receiver of claim 1,wherein the communication/control circuit is configured to use an out ofband communication with an authenticated link as a communicationchannel.
 3. The wireless power receiver of claim 2, wherein thecommunication/control circuit is configured to count an authenticationpermission time from a last packet exchange time by an in-bandcommunication.
 4. The wireless power receiver of claim 1, wherein thecommunication/control circuit is configured to exchange a public keywith the wireless power transmitter in an authentication phase with thewireless power transmitter.
 5. The wireless power receiver of claim 4,wherein the public key is an elliptic curve Diffie-Hellman (ECDH) keywhich is newly generated each authentication.
 6. The wireless powerreceiver of claim 5, wherein the communication/control circuit isconfigured to repeatedly switch a relationship between an authenticationinitiator and an authentication responder with the wireless powertransmitter after handover to an out of band communication in theauthentication phase with the wireless power transmitter, wherein theauthentication responder transmits an authentication response message(CHALLENGE_AUTH) including a public key in response to an authenticationrequest message (CHALLENGE) of the authentication initiator.
 7. Thewireless power receiver of claim 6, wherein the authentication responsemessage includes a signature based on an authentication.
 8. The wirelesspower receiver of claim 1, wherein, after an authentication with thewireless power transmitter is completed and an authenticationcertificate is exchanged with each other, the communication/controlcircuit is configured to exchange a public key with the wireless powertransmitter.
 9. The wireless power receiver of claim 8, wherein thepublic key is an elliptic curve Diffie-Hellman (ECDH) key.
 10. Thewireless power receiver of claim 9, wherein the communication/controlcircuit is configured to: when the wireless power receiver is anauthentication initiator, generate a first public key and a firstsignature, transmit a public key request message including the firstpublic key and the first signature to the wireless power transmitter,and verify a second signature of a public key response message receivedfrom the wireless power transmitter with a public key for anauthentication responder's authentication certificate.
 11. The wirelesspower receiver of claim 9, wherein the communication/control circuit isconfigured to: when the wireless power receiver is an authenticationresponder, receive a public key request message from the wireless powertransmitter; verify a first signature of the public key request messagereceived from the wireless power transmitter with a public key of anauthentication initiator's authentication certificate, generate a secondpublic key and a second signature, transmit a public key responsemessage including the second public key and the second signature to thewireless power transmitter.
 12. (canceled)
 13. A wireless powertransmitter, comprising: a power conversion circuit configured to form amagnetic coupling with a wireless power receiver to transmit wirelesspower to the wireless power receiver; and a communication/controlcircuit configured to perform at least one of transmission control ofthe wireless power and transmission and reception of data based oncommunication with the wireless power receiver, wherein thecommunication/control circuit is configured to initiate a creationprocess of an authenticated link for charging by accepting only aconnect request received within a predetermined authentication acceptperiod.
 14. The wireless power transmitter of claim 13, wherein thecommunication/control circuit is configured to use an out of bandcommunication with an authenticated link as a communication channel. 15.The wireless power transmitter of claim 14, wherein thecommunication/control circuit is configured to count an authenticationpermission time from a last packet exchange time by an in-bandcommunication.
 16. The wireless power transmitter of claim 13, whereinthe communication/control circuit is configured to exchange a public keywith the wireless power receiver in an authentication phase with thewireless power receiver.
 17. The wireless power transmitter of claim 16,wherein the public key is an elliptic curve Diffie-Hellman (ECDH) keywhich is newly generated each authentication.
 18. The wireless powertransmitter of claim 17, wherein the communication/control circuit isconfigured to repeatedly switch a relationship between an authenticationinitiator and an authentication responder with the wireless powerreceiver after handover to an out of band communication in theauthentication phase with the wireless power receiver, wherein theauthentication responder transmits an authentication response message(CHALLENGE_AUTH) including a public key in response to an authenticationrequest message (CHALLENGE) of the authentication initiator.
 19. Thewireless power transmitter of claim 18, wherein the authenticationresponse message includes a signature based on an authentication. 20.The wireless power transmitter of claim 13, wherein, after anauthentication with the wireless power receiver is completed and anauthentication certificate is exchanged with each other, thecommunication/control circuit is configured to exchange a public keywith the wireless power receiver.
 21. The wireless power transmitter ofclaim 20, wherein the public key is an elliptic curve Diffie-Hellman(ECDH) key. 22-24. (canceled)